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LU-10239 osc: limit chunk number of write submit
[fs/lustre-release.git] / lustre / osc / osc_cache.c
1 /*
2  * GPL HEADER START
3  *
4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 only,
8  * as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * General Public License version 2 for more details (a copy is included
14  * in the LICENSE file that accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License
17  * version 2 along with this program; If not, see
18  * http://www.gnu.org/licenses/gpl-2.0.html
19  *
20  * GPL HEADER END
21  */
22 /*
23  * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
24  * Use is subject to license terms.
25  *
26  * Copyright (c) 2012, 2017, Intel Corporation.
27  *
28  */
29 /*
30  * This file is part of Lustre, http://www.lustre.org/
31  * Lustre is a trademark of Sun Microsystems, Inc.
32  *
33  * osc cache management.
34  *
35  * Author: Jinshan Xiong <jinshan.xiong@whamcloud.com>
36  */
37
38 #define DEBUG_SUBSYSTEM S_OSC
39
40 #include <lustre_osc.h>
41
42 #include "osc_internal.h"
43
44 static int extent_debug; /* set it to be true for more debug */
45
46 static void osc_update_pending(struct osc_object *obj, int cmd, int delta);
47 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
48                            enum osc_extent_state state);
49 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
50                               struct osc_async_page *oap, int sent, int rc);
51 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
52                           int cmd);
53 static int osc_refresh_count(const struct lu_env *env,
54                              struct osc_async_page *oap, int cmd);
55 static int osc_io_unplug_async(const struct lu_env *env,
56                                struct client_obd *cli, struct osc_object *osc);
57 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
58                            unsigned int lost_grant, unsigned int dirty_grant);
59
60 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
61                                   const char *func, int line);
62 #define osc_extent_tree_dump(lvl, obj) \
63         osc_extent_tree_dump0(lvl, obj, __func__, __LINE__)
64
65 static void osc_unreserve_grant(struct client_obd *cli, unsigned int reserved,
66                                 unsigned int unused);
67
68 /** \addtogroup osc
69  *  @{
70  */
71
72 /* ------------------ osc extent ------------------ */
73 static inline char *ext_flags(struct osc_extent *ext, char *flags)
74 {
75         char *buf = flags;
76         *buf++ = ext->oe_rw ? 'r' : 'w';
77         if (ext->oe_intree)
78                 *buf++ = 'i';
79         if (ext->oe_sync)
80                 *buf++ = 'S';
81         if (ext->oe_srvlock)
82                 *buf++ = 's';
83         if (ext->oe_hp)
84                 *buf++ = 'h';
85         if (ext->oe_urgent)
86                 *buf++ = 'u';
87         if (ext->oe_memalloc)
88                 *buf++ = 'm';
89         if (ext->oe_trunc_pending)
90                 *buf++ = 't';
91         if (ext->oe_fsync_wait)
92                 *buf++ = 'Y';
93         *buf = 0;
94         return flags;
95 }
96
97 static inline char list_empty_marker(struct list_head *list)
98 {
99         return list_empty(list) ? '-' : '+';
100 }
101
102 #define EXTSTR       "[%lu -> %lu/%lu]"
103 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
104 static const char *oes_strings[] = {
105         "inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
106
107 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {                           \
108         struct osc_extent *__ext = (extent);                                  \
109         char __buf[16];                                                       \
110                                                                               \
111         CDEBUG(lvl,                                                           \
112                 "extent %p@{" EXTSTR ", "                                     \
113                 "[%d|%d|%c|%s|%s|%p], [%d|%d|%c|%c|%p|%u|%p]} " fmt,          \
114                 /* ----- extent part 0 ----- */                               \
115                 __ext, EXTPARA(__ext),                                        \
116                 /* ----- part 1 ----- */                                      \
117                 atomic_read(&__ext->oe_refc),                         \
118                 atomic_read(&__ext->oe_users),                        \
119                 list_empty_marker(&__ext->oe_link),                           \
120                 oes_strings[__ext->oe_state], ext_flags(__ext, __buf),        \
121                 __ext->oe_obj,                                                \
122                 /* ----- part 2 ----- */                                      \
123                 __ext->oe_grants, __ext->oe_nr_pages,                         \
124                 list_empty_marker(&__ext->oe_pages),                          \
125                 waitqueue_active(&__ext->oe_waitq) ? '+' : '-',               \
126                 __ext->oe_dlmlock, __ext->oe_mppr, __ext->oe_owner,           \
127                 /* ----- part 4 ----- */                                      \
128                 ## __VA_ARGS__);                                              \
129         if (lvl == D_ERROR && __ext->oe_dlmlock != NULL)                      \
130                 LDLM_ERROR(__ext->oe_dlmlock, "extent: %p", __ext);           \
131         else                                                                  \
132                 LDLM_DEBUG(__ext->oe_dlmlock, "extent: %p", __ext);           \
133 } while (0)
134
135 #undef EASSERTF
136 #define EASSERTF(expr, ext, fmt, args...) do {                          \
137         if (!(expr)) {                                                  \
138                 OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);           \
139                 osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);           \
140                 LASSERT(expr);                                          \
141         }                                                               \
142 } while (0)
143
144 #undef EASSERT
145 #define EASSERT(expr, ext) EASSERTF(expr, ext, "\n")
146
147 static inline struct osc_extent *rb_extent(struct rb_node *n)
148 {
149         if (n == NULL)
150                 return NULL;
151
152         return container_of(n, struct osc_extent, oe_node);
153 }
154
155 static inline struct osc_extent *next_extent(struct osc_extent *ext)
156 {
157         if (ext == NULL)
158                 return NULL;
159
160         LASSERT(ext->oe_intree);
161         return rb_extent(rb_next(&ext->oe_node));
162 }
163
164 static inline struct osc_extent *prev_extent(struct osc_extent *ext)
165 {
166         if (ext == NULL)
167                 return NULL;
168
169         LASSERT(ext->oe_intree);
170         return rb_extent(rb_prev(&ext->oe_node));
171 }
172
173 static inline struct osc_extent *first_extent(struct osc_object *obj)
174 {
175         return rb_extent(rb_first(&obj->oo_root));
176 }
177
178 /* object must be locked by caller. */
179 static int osc_extent_sanity_check0(struct osc_extent *ext,
180                                     const char *func, const int line)
181 {
182         struct osc_object *obj = ext->oe_obj;
183         struct osc_async_page *oap;
184         size_t page_count;
185         int rc = 0;
186
187         if (!osc_object_is_locked(obj))
188                 GOTO(out, rc = 9);
189
190         if (ext->oe_state >= OES_STATE_MAX)
191                 GOTO(out, rc = 10);
192
193         if (atomic_read(&ext->oe_refc) <= 0)
194                 GOTO(out, rc = 20);
195
196         if (atomic_read(&ext->oe_refc) < atomic_read(&ext->oe_users))
197                 GOTO(out, rc = 30);
198
199         switch (ext->oe_state) {
200         case OES_INV:
201                 if (ext->oe_nr_pages > 0 || !list_empty(&ext->oe_pages))
202                         GOTO(out, rc = 35);
203                 GOTO(out, rc = 0);
204                 break;
205         case OES_ACTIVE:
206                 if (atomic_read(&ext->oe_users) == 0)
207                         GOTO(out, rc = 40);
208                 if (ext->oe_hp)
209                         GOTO(out, rc = 50);
210                 if (ext->oe_fsync_wait && !ext->oe_urgent)
211                         GOTO(out, rc = 55);
212                 break;
213         case OES_CACHE:
214                 if (ext->oe_grants == 0)
215                         GOTO(out, rc = 60);
216                 if (ext->oe_fsync_wait && !ext->oe_urgent && !ext->oe_hp)
217                         GOTO(out, rc = 65);
218         default:
219                 if (atomic_read(&ext->oe_users) > 0)
220                         GOTO(out, rc = 70);
221         }
222
223         if (ext->oe_max_end < ext->oe_end || ext->oe_end < ext->oe_start)
224                 GOTO(out, rc = 80);
225
226         if (ext->oe_sync && ext->oe_grants > 0)
227                 GOTO(out, rc = 90);
228
229         if (ext->oe_dlmlock != NULL &&
230             ext->oe_dlmlock->l_resource->lr_type == LDLM_EXTENT &&
231             !ldlm_is_failed(ext->oe_dlmlock)) {
232                 struct ldlm_extent *extent;
233
234                 extent = &ext->oe_dlmlock->l_policy_data.l_extent;
235                 if (!(extent->start <= cl_offset(osc2cl(obj), ext->oe_start) &&
236                       extent->end   >= cl_offset(osc2cl(obj), ext->oe_max_end)))
237                         GOTO(out, rc = 100);
238
239                 if (!(ext->oe_dlmlock->l_granted_mode & (LCK_PW | LCK_GROUP)))
240                         GOTO(out, rc = 102);
241         }
242
243         if (ext->oe_nr_pages > ext->oe_mppr)
244                 GOTO(out, rc = 105);
245
246         /* Do not verify page list if extent is in RPC. This is because an
247          * in-RPC extent is supposed to be exclusively accessible w/o lock. */
248         if (ext->oe_state > OES_CACHE)
249                 GOTO(out, rc = 0);
250
251         if (!extent_debug)
252                 GOTO(out, rc = 0);
253
254         page_count = 0;
255         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
256                 pgoff_t index = osc_index(oap2osc(oap));
257                 ++page_count;
258                 if (index > ext->oe_end || index < ext->oe_start)
259                         GOTO(out, rc = 110);
260         }
261         if (page_count != ext->oe_nr_pages)
262                 GOTO(out, rc = 120);
263
264 out:
265         if (rc != 0)
266                 OSC_EXTENT_DUMP(D_ERROR, ext,
267                                 "%s:%d sanity check %p failed with rc = %d\n",
268                                 func, line, ext, rc);
269         return rc;
270 }
271
272 #define sanity_check_nolock(ext) \
273         osc_extent_sanity_check0(ext, __func__, __LINE__)
274
275 #define sanity_check(ext) ({                                                   \
276         int __res;                                                             \
277         osc_object_lock((ext)->oe_obj);                                        \
278         __res = sanity_check_nolock(ext);                                      \
279         osc_object_unlock((ext)->oe_obj);                                      \
280         __res;                                                                 \
281 })
282
283
284 /**
285  * sanity check - to make sure there is no overlapped extent in the tree.
286  */
287 static int osc_extent_is_overlapped(struct osc_object *obj,
288                                     struct osc_extent *ext)
289 {
290         struct osc_extent *tmp;
291
292         LASSERT(osc_object_is_locked(obj));
293
294         if (!extent_debug)
295                 return 0;
296
297         for (tmp = first_extent(obj); tmp != NULL; tmp = next_extent(tmp)) {
298                 if (tmp == ext)
299                         continue;
300                 if (tmp->oe_end >= ext->oe_start &&
301                     tmp->oe_start <= ext->oe_end)
302                         return 1;
303         }
304         return 0;
305 }
306
307 static void osc_extent_state_set(struct osc_extent *ext, int state)
308 {
309         LASSERT(osc_object_is_locked(ext->oe_obj));
310         LASSERT(state >= OES_INV && state < OES_STATE_MAX);
311
312         /* Never try to sanity check a state changing extent :-) */
313         /* LASSERT(sanity_check_nolock(ext) == 0); */
314
315         /* TODO: validate the state machine */
316         ext->oe_state = state;
317         wake_up_all(&ext->oe_waitq);
318 }
319
320 static struct osc_extent *osc_extent_alloc(struct osc_object *obj)
321 {
322         struct osc_extent *ext;
323
324         OBD_SLAB_ALLOC_PTR_GFP(ext, osc_extent_kmem, GFP_NOFS);
325         if (ext == NULL)
326                 return NULL;
327
328         RB_CLEAR_NODE(&ext->oe_node);
329         ext->oe_obj = obj;
330         cl_object_get(osc2cl(obj));
331         atomic_set(&ext->oe_refc, 1);
332         atomic_set(&ext->oe_users, 0);
333         INIT_LIST_HEAD(&ext->oe_link);
334         ext->oe_state = OES_INV;
335         INIT_LIST_HEAD(&ext->oe_pages);
336         init_waitqueue_head(&ext->oe_waitq);
337         ext->oe_dlmlock = NULL;
338
339         return ext;
340 }
341
342 static void osc_extent_free(struct osc_extent *ext)
343 {
344         OBD_SLAB_FREE_PTR(ext, osc_extent_kmem);
345 }
346
347 static struct osc_extent *osc_extent_get(struct osc_extent *ext)
348 {
349         LASSERT(atomic_read(&ext->oe_refc) >= 0);
350         atomic_inc(&ext->oe_refc);
351         return ext;
352 }
353
354 static void osc_extent_put(const struct lu_env *env, struct osc_extent *ext)
355 {
356         LASSERT(atomic_read(&ext->oe_refc) > 0);
357         if (atomic_dec_and_test(&ext->oe_refc)) {
358                 LASSERT(list_empty(&ext->oe_link));
359                 LASSERT(atomic_read(&ext->oe_users) == 0);
360                 LASSERT(ext->oe_state == OES_INV);
361                 LASSERT(!ext->oe_intree);
362
363                 if (ext->oe_dlmlock != NULL) {
364                         lu_ref_add(&ext->oe_dlmlock->l_reference,
365                                    "osc_extent", ext);
366                         LDLM_LOCK_PUT(ext->oe_dlmlock);
367                         ext->oe_dlmlock = NULL;
368                 }
369                 cl_object_put(env, osc2cl(ext->oe_obj));
370                 osc_extent_free(ext);
371         }
372 }
373
374 /**
375  * osc_extent_put_trust() is a special version of osc_extent_put() when
376  * it's known that the caller is not the last user. This is to address the
377  * problem of lacking of lu_env ;-).
378  */
379 static void osc_extent_put_trust(struct osc_extent *ext)
380 {
381         LASSERT(atomic_read(&ext->oe_refc) > 1);
382         LASSERT(osc_object_is_locked(ext->oe_obj));
383         atomic_dec(&ext->oe_refc);
384 }
385
386 /**
387  * Return the extent which includes pgoff @index, or return the greatest
388  * previous extent in the tree.
389  */
390 static struct osc_extent *osc_extent_search(struct osc_object *obj,
391                                             pgoff_t index)
392 {
393         struct rb_node    *n = obj->oo_root.rb_node;
394         struct osc_extent *tmp, *p = NULL;
395
396         LASSERT(osc_object_is_locked(obj));
397         while (n != NULL) {
398                 tmp = rb_extent(n);
399                 if (index < tmp->oe_start) {
400                         n = n->rb_left;
401                 } else if (index > tmp->oe_end) {
402                         p = rb_extent(n);
403                         n = n->rb_right;
404                 } else {
405                         return tmp;
406                 }
407         }
408         return p;
409 }
410
411 /*
412  * Return the extent covering @index, otherwise return NULL.
413  * caller must have held object lock.
414  */
415 static struct osc_extent *osc_extent_lookup(struct osc_object *obj,
416                                             pgoff_t index)
417 {
418         struct osc_extent *ext;
419
420         ext = osc_extent_search(obj, index);
421         if (ext != NULL && ext->oe_start <= index && index <= ext->oe_end)
422                 return osc_extent_get(ext);
423         return NULL;
424 }
425
426 /* caller must have held object lock. */
427 static void osc_extent_insert(struct osc_object *obj, struct osc_extent *ext)
428 {
429         struct rb_node   **n      = &obj->oo_root.rb_node;
430         struct rb_node    *parent = NULL;
431         struct osc_extent *tmp;
432
433         LASSERT(ext->oe_intree == 0);
434         LASSERT(ext->oe_obj == obj);
435         LASSERT(osc_object_is_locked(obj));
436         while (*n != NULL) {
437                 tmp = rb_extent(*n);
438                 parent = *n;
439
440                 if (ext->oe_end < tmp->oe_start)
441                         n = &(*n)->rb_left;
442                 else if (ext->oe_start > tmp->oe_end)
443                         n = &(*n)->rb_right;
444                 else
445                         EASSERTF(0, tmp, EXTSTR"\n", EXTPARA(ext));
446         }
447         rb_link_node(&ext->oe_node, parent, n);
448         rb_insert_color(&ext->oe_node, &obj->oo_root);
449         osc_extent_get(ext);
450         ext->oe_intree = 1;
451 }
452
453 /* caller must have held object lock. */
454 static void osc_extent_erase(struct osc_extent *ext)
455 {
456         struct osc_object *obj = ext->oe_obj;
457         LASSERT(osc_object_is_locked(obj));
458         if (ext->oe_intree) {
459                 rb_erase(&ext->oe_node, &obj->oo_root);
460                 ext->oe_intree = 0;
461                 /* rbtree held a refcount */
462                 osc_extent_put_trust(ext);
463         }
464 }
465
466 static struct osc_extent *osc_extent_hold(struct osc_extent *ext)
467 {
468         struct osc_object *obj = ext->oe_obj;
469
470         LASSERT(osc_object_is_locked(obj));
471         LASSERT(ext->oe_state == OES_ACTIVE || ext->oe_state == OES_CACHE);
472         if (ext->oe_state == OES_CACHE) {
473                 osc_extent_state_set(ext, OES_ACTIVE);
474                 osc_update_pending(obj, OBD_BRW_WRITE, -ext->oe_nr_pages);
475         }
476         atomic_inc(&ext->oe_users);
477         list_del_init(&ext->oe_link);
478         return osc_extent_get(ext);
479 }
480
481 static void __osc_extent_remove(struct osc_extent *ext)
482 {
483         LASSERT(osc_object_is_locked(ext->oe_obj));
484         LASSERT(list_empty(&ext->oe_pages));
485         osc_extent_erase(ext);
486         list_del_init(&ext->oe_link);
487         osc_extent_state_set(ext, OES_INV);
488         OSC_EXTENT_DUMP(D_CACHE, ext, "destroyed.\n");
489 }
490
491 static void osc_extent_remove(struct osc_extent *ext)
492 {
493         struct osc_object *obj = ext->oe_obj;
494
495         osc_object_lock(obj);
496         __osc_extent_remove(ext);
497         osc_object_unlock(obj);
498 }
499
500 /**
501  * This function is used to merge extents to get better performance. It checks
502  * if @cur and @victim are contiguous at block level.
503  */
504 static int osc_extent_merge(const struct lu_env *env, struct osc_extent *cur,
505                             struct osc_extent *victim)
506 {
507         struct osc_object       *obj = cur->oe_obj;
508         struct client_obd       *cli = osc_cli(obj);
509         pgoff_t                  chunk_start;
510         pgoff_t                  chunk_end;
511         int                      ppc_bits;
512
513         LASSERT(cur->oe_state == OES_CACHE);
514         LASSERT(osc_object_is_locked(obj));
515         if (victim == NULL)
516                 return -EINVAL;
517
518         if (victim->oe_state != OES_CACHE || victim->oe_fsync_wait)
519                 return -EBUSY;
520
521         if (cur->oe_max_end != victim->oe_max_end)
522                 return -ERANGE;
523
524         LASSERT(cur->oe_dlmlock == victim->oe_dlmlock);
525         ppc_bits = osc_cli(obj)->cl_chunkbits - PAGE_SHIFT;
526         chunk_start = cur->oe_start >> ppc_bits;
527         chunk_end   = cur->oe_end   >> ppc_bits;
528         if (chunk_start   != (victim->oe_end >> ppc_bits) + 1 &&
529             chunk_end + 1 != victim->oe_start >> ppc_bits)
530                 return -ERANGE;
531
532         /* overall extent size should not exceed the max supported limit
533          * reported by the server */
534         if (cur->oe_end - cur->oe_start + 1 +
535             victim->oe_end - victim->oe_start + 1 > cli->cl_max_extent_pages)
536                 return -ERANGE;
537
538         OSC_EXTENT_DUMP(D_CACHE, victim, "will be merged by %p.\n", cur);
539
540         cur->oe_start     = min(cur->oe_start, victim->oe_start);
541         cur->oe_end       = max(cur->oe_end,   victim->oe_end);
542         /* per-extent tax should be accounted only once for the whole extent */
543         cur->oe_grants   += victim->oe_grants - cli->cl_grant_extent_tax;
544         cur->oe_nr_pages += victim->oe_nr_pages;
545         /* only the following bits are needed to merge */
546         cur->oe_urgent   |= victim->oe_urgent;
547         cur->oe_memalloc |= victim->oe_memalloc;
548         list_splice_init(&victim->oe_pages, &cur->oe_pages);
549         list_del_init(&victim->oe_link);
550         victim->oe_nr_pages = 0;
551
552         osc_extent_get(victim);
553         __osc_extent_remove(victim);
554         osc_extent_put(env, victim);
555
556         OSC_EXTENT_DUMP(D_CACHE, cur, "after merging %p.\n", victim);
557         return 0;
558 }
559
560 /**
561  * Drop user count of osc_extent, and unplug IO asynchronously.
562  */
563 int osc_extent_release(const struct lu_env *env, struct osc_extent *ext)
564 {
565         struct osc_object *obj = ext->oe_obj;
566         struct client_obd *cli = osc_cli(obj);
567         int rc = 0;
568         ENTRY;
569
570         LASSERT(atomic_read(&ext->oe_users) > 0);
571         LASSERT(sanity_check(ext) == 0);
572         LASSERT(ext->oe_grants > 0);
573
574         if (atomic_dec_and_lock(&ext->oe_users, &obj->oo_lock)) {
575                 LASSERT(ext->oe_state == OES_ACTIVE);
576                 if (ext->oe_trunc_pending) {
577                         /* a truncate process is waiting for this extent.
578                          * This may happen due to a race, check
579                          * osc_cache_truncate_start(). */
580                         osc_extent_state_set(ext, OES_TRUNC);
581                         ext->oe_trunc_pending = 0;
582                 } else {
583                         int grant = 0;
584
585                         osc_extent_state_set(ext, OES_CACHE);
586                         osc_update_pending(obj, OBD_BRW_WRITE,
587                                            ext->oe_nr_pages);
588
589                         /* try to merge the previous and next extent. */
590                         if (osc_extent_merge(env, ext, prev_extent(ext)) == 0)
591                                 grant += cli->cl_grant_extent_tax;
592                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
593                                 grant += cli->cl_grant_extent_tax;
594                         if (grant > 0)
595                                 osc_unreserve_grant(cli, 0, grant);
596
597                         if (ext->oe_urgent)
598                                 list_move_tail(&ext->oe_link,
599                                                &obj->oo_urgent_exts);
600                         else if (ext->oe_nr_pages == ext->oe_mppr) {
601                                 list_move_tail(&ext->oe_link,
602                                                &obj->oo_full_exts);
603                         }
604                 }
605                 osc_object_unlock(obj);
606
607                 osc_io_unplug_async(env, cli, obj);
608         }
609         osc_extent_put(env, ext);
610         RETURN(rc);
611 }
612
613 static inline int overlapped(struct osc_extent *ex1, struct osc_extent *ex2)
614 {
615         return !(ex1->oe_end < ex2->oe_start || ex2->oe_end < ex1->oe_start);
616 }
617
618 /**
619  * Find or create an extent which includes @index, core function to manage
620  * extent tree.
621  */
622 static struct osc_extent *osc_extent_find(const struct lu_env *env,
623                                           struct osc_object *obj, pgoff_t index,
624                                           unsigned int *grants)
625 {
626         struct client_obd *cli = osc_cli(obj);
627         struct osc_lock   *olck;
628         struct cl_lock_descr *descr;
629         struct osc_extent *cur;
630         struct osc_extent *ext;
631         struct osc_extent *conflict = NULL;
632         struct osc_extent *found = NULL;
633         pgoff_t    chunk;
634         pgoff_t    max_end;
635         unsigned int max_pages; /* max_pages_per_rpc */
636         unsigned int chunksize;
637         int        ppc_bits; /* pages per chunk bits */
638         pgoff_t    chunk_mask;
639         int        rc;
640         ENTRY;
641
642         cur = osc_extent_alloc(obj);
643         if (cur == NULL)
644                 RETURN(ERR_PTR(-ENOMEM));
645
646         olck = osc_env_io(env)->oi_write_osclock;
647         LASSERTF(olck != NULL, "page %lu is not covered by lock\n", index);
648         LASSERT(olck->ols_state == OLS_GRANTED);
649
650         descr = &olck->ols_cl.cls_lock->cll_descr;
651         LASSERT(descr->cld_mode >= CLM_WRITE);
652
653         LASSERTF(cli->cl_chunkbits >= PAGE_SHIFT,
654                  "chunkbits: %u\n", cli->cl_chunkbits);
655         ppc_bits   = cli->cl_chunkbits - PAGE_SHIFT;
656         chunk_mask = ~((1 << ppc_bits) - 1);
657         chunksize  = 1 << cli->cl_chunkbits;
658         chunk      = index >> ppc_bits;
659
660         /* align end to RPC edge. */
661         max_pages = cli->cl_max_pages_per_rpc;
662         if ((max_pages & ~chunk_mask) != 0) {
663                 CERROR("max_pages: %#x chunkbits: %u chunk_mask: %#lx\n",
664                        max_pages, cli->cl_chunkbits, chunk_mask);
665                 RETURN(ERR_PTR(-EINVAL));
666         }
667         max_end = index - (index % max_pages) + max_pages - 1;
668         max_end = min_t(pgoff_t, max_end, descr->cld_end);
669
670         /* initialize new extent by parameters so far */
671         cur->oe_max_end = max_end;
672         cur->oe_start   = index & chunk_mask;
673         cur->oe_end     = ((index + ~chunk_mask + 1) & chunk_mask) - 1;
674         if (cur->oe_start < descr->cld_start)
675                 cur->oe_start = descr->cld_start;
676         if (cur->oe_end > max_end)
677                 cur->oe_end = max_end;
678         cur->oe_grants  = 0;
679         cur->oe_mppr    = max_pages;
680         if (olck->ols_dlmlock != NULL) {
681                 LASSERT(olck->ols_hold);
682                 cur->oe_dlmlock = LDLM_LOCK_GET(olck->ols_dlmlock);
683                 lu_ref_add(&olck->ols_dlmlock->l_reference, "osc_extent", cur);
684         }
685
686         /* grants has been allocated by caller */
687         LASSERTF(*grants >= chunksize + cli->cl_grant_extent_tax,
688                  "%u/%u/%u.\n", *grants, chunksize, cli->cl_grant_extent_tax);
689         LASSERTF((max_end - cur->oe_start) < max_pages, EXTSTR"\n",
690                  EXTPARA(cur));
691
692 restart:
693         osc_object_lock(obj);
694         ext = osc_extent_search(obj, cur->oe_start);
695         if (ext == NULL)
696                 ext = first_extent(obj);
697         while (ext != NULL) {
698                 pgoff_t ext_chk_start = ext->oe_start >> ppc_bits;
699                 pgoff_t ext_chk_end   = ext->oe_end   >> ppc_bits;
700
701                 LASSERT(sanity_check_nolock(ext) == 0);
702                 if (chunk > ext_chk_end + 1 || chunk < ext_chk_start)
703                         break;
704
705                 /* if covering by different locks, no chance to match */
706                 if (olck->ols_dlmlock != ext->oe_dlmlock) {
707                         EASSERTF(!overlapped(ext, cur), ext,
708                                  EXTSTR"\n", EXTPARA(cur));
709
710                         ext = next_extent(ext);
711                         continue;
712                 }
713
714                 /* discontiguous chunks? */
715                 if (chunk + 1 < ext_chk_start) {
716                         ext = next_extent(ext);
717                         continue;
718                 }
719
720                 /* ok, from now on, ext and cur have these attrs:
721                  * 1. covered by the same lock
722                  * 2. contiguous at chunk level or overlapping. */
723
724                 if (overlapped(ext, cur)) {
725                         /* cur is the minimum unit, so overlapping means
726                          * full contain. */
727                         EASSERTF((ext->oe_start <= cur->oe_start &&
728                                   ext->oe_end >= cur->oe_end),
729                                  ext, EXTSTR"\n", EXTPARA(cur));
730
731                         if (ext->oe_state > OES_CACHE || ext->oe_fsync_wait) {
732                                 /* for simplicity, we wait for this extent to
733                                  * finish before going forward. */
734                                 conflict = osc_extent_get(ext);
735                                 break;
736                         }
737
738                         found = osc_extent_hold(ext);
739                         break;
740                 }
741
742                 /* non-overlapped extent */
743                 if (ext->oe_state != OES_CACHE || ext->oe_fsync_wait) {
744                         /* we can't do anything for a non OES_CACHE extent, or
745                          * if there is someone waiting for this extent to be
746                          * flushed, try next one. */
747                         ext = next_extent(ext);
748                         continue;
749                 }
750
751                 /* check if they belong to the same rpc slot before trying to
752                  * merge. the extents are not overlapped and contiguous at
753                  * chunk level to get here. */
754                 if (ext->oe_max_end != max_end) {
755                         /* if they don't belong to the same RPC slot or
756                          * max_pages_per_rpc has ever changed, do not merge. */
757                         ext = next_extent(ext);
758                         continue;
759                 }
760
761                 /* check whether maximum extent size will be hit */
762                 if ((ext_chk_end - ext_chk_start + 1 + 1) << ppc_bits >
763                     cli->cl_max_extent_pages) {
764                         ext = next_extent(ext);
765                         continue;
766                 }
767
768                 /* it's required that an extent must be contiguous at chunk
769                  * level so that we know the whole extent is covered by grant
770                  * (the pages in the extent are NOT required to be contiguous).
771                  * Otherwise, it will be too much difficult to know which
772                  * chunks have grants allocated. */
773
774                 /* try to do front merge - extend ext's start */
775                 if (chunk + 1 == ext_chk_start) {
776                         /* ext must be chunk size aligned */
777                         EASSERT((ext->oe_start & ~chunk_mask) == 0, ext);
778
779                         /* pull ext's start back to cover cur */
780                         ext->oe_start   = cur->oe_start;
781                         ext->oe_grants += chunksize;
782                         LASSERT(*grants >= chunksize);
783                         *grants -= chunksize;
784
785                         found = osc_extent_hold(ext);
786                 } else if (chunk == ext_chk_end + 1) {
787                         /* rear merge */
788                         ext->oe_end     = cur->oe_end;
789                         ext->oe_grants += chunksize;
790                         LASSERT(*grants >= chunksize);
791                         *grants -= chunksize;
792
793                         /* try to merge with the next one because we just fill
794                          * in a gap */
795                         if (osc_extent_merge(env, ext, next_extent(ext)) == 0)
796                                 /* we can save extent tax from next extent */
797                                 *grants += cli->cl_grant_extent_tax;
798
799                         found = osc_extent_hold(ext);
800                 }
801                 if (found != NULL)
802                         break;
803
804                 ext = next_extent(ext);
805         }
806
807         osc_extent_tree_dump(D_CACHE, obj);
808         if (found != NULL) {
809                 LASSERT(conflict == NULL);
810                 if (!IS_ERR(found)) {
811                         LASSERT(found->oe_dlmlock == cur->oe_dlmlock);
812                         OSC_EXTENT_DUMP(D_CACHE, found,
813                                         "found caching ext for %lu.\n", index);
814                 }
815         } else if (conflict == NULL) {
816                 /* create a new extent */
817                 EASSERT(osc_extent_is_overlapped(obj, cur) == 0, cur);
818                 cur->oe_grants = chunksize + cli->cl_grant_extent_tax;
819                 LASSERT(*grants >= cur->oe_grants);
820                 *grants -= cur->oe_grants;
821
822                 cur->oe_state = OES_CACHE;
823                 found = osc_extent_hold(cur);
824                 osc_extent_insert(obj, cur);
825                 OSC_EXTENT_DUMP(D_CACHE, cur, "add into tree %lu/%lu.\n",
826                                 index, descr->cld_end);
827         }
828         osc_object_unlock(obj);
829
830         if (conflict != NULL) {
831                 LASSERT(found == NULL);
832
833                 /* waiting for IO to finish. Please notice that it's impossible
834                  * to be an OES_TRUNC extent. */
835                 rc = osc_extent_wait(env, conflict, OES_INV);
836                 osc_extent_put(env, conflict);
837                 conflict = NULL;
838                 if (rc < 0)
839                         GOTO(out, found = ERR_PTR(rc));
840
841                 goto restart;
842         }
843         EXIT;
844
845 out:
846         osc_extent_put(env, cur);
847         return found;
848 }
849
850 /**
851  * Called when IO is finished to an extent.
852  */
853 int osc_extent_finish(const struct lu_env *env, struct osc_extent *ext,
854                       int sent, int rc)
855 {
856         struct client_obd *cli = osc_cli(ext->oe_obj);
857         struct osc_async_page *oap;
858         struct osc_async_page *tmp;
859         int nr_pages = ext->oe_nr_pages;
860         int lost_grant = 0;
861         int blocksize = cli->cl_import->imp_obd->obd_osfs.os_bsize ? : 4096;
862         loff_t last_off = 0;
863         int last_count = -1;
864         ENTRY;
865
866         OSC_EXTENT_DUMP(D_CACHE, ext, "extent finished.\n");
867
868         ext->oe_rc = rc ?: ext->oe_nr_pages;
869         EASSERT(ergo(rc == 0, ext->oe_state == OES_RPC), ext);
870
871         osc_lru_add_batch(cli, &ext->oe_pages);
872         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
873                                      oap_pending_item) {
874                 list_del_init(&oap->oap_rpc_item);
875                 list_del_init(&oap->oap_pending_item);
876                 if (last_off <= oap->oap_obj_off) {
877                         last_off = oap->oap_obj_off;
878                         last_count = oap->oap_count;
879                 }
880
881                 --ext->oe_nr_pages;
882                 osc_ap_completion(env, cli, oap, sent, rc);
883         }
884         EASSERT(ext->oe_nr_pages == 0, ext);
885
886         if (!sent) {
887                 lost_grant = ext->oe_grants;
888         } else if (blocksize < PAGE_SIZE &&
889                    last_count != PAGE_SIZE) {
890                 /* For short writes we shouldn't count parts of pages that
891                  * span a whole chunk on the OST side, or our accounting goes
892                  * wrong.  Should match the code in filter_grant_check. */
893                 int offset = last_off & ~PAGE_MASK;
894                 int count = last_count + (offset & (blocksize - 1));
895                 int end = (offset + last_count) & (blocksize - 1);
896                 if (end)
897                         count += blocksize - end;
898
899                 lost_grant = PAGE_SIZE - count;
900         }
901         if (ext->oe_grants > 0)
902                 osc_free_grant(cli, nr_pages, lost_grant, ext->oe_grants);
903
904         osc_extent_remove(ext);
905         /* put the refcount for RPC */
906         osc_extent_put(env, ext);
907         RETURN(0);
908 }
909
910 static int extent_wait_cb(struct osc_extent *ext, enum osc_extent_state state)
911 {
912         int ret;
913
914         osc_object_lock(ext->oe_obj);
915         ret = ext->oe_state == state;
916         osc_object_unlock(ext->oe_obj);
917
918         return ret;
919 }
920
921 /**
922  * Wait for the extent's state to become @state.
923  */
924 static int osc_extent_wait(const struct lu_env *env, struct osc_extent *ext,
925                            enum osc_extent_state state)
926 {
927         struct osc_object *obj = ext->oe_obj;
928         struct l_wait_info lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(600), NULL,
929                                                   LWI_ON_SIGNAL_NOOP, NULL);
930         int rc = 0;
931         ENTRY;
932
933         osc_object_lock(obj);
934         LASSERT(sanity_check_nolock(ext) == 0);
935         /* `Kick' this extent only if the caller is waiting for it to be
936          * written out. */
937         if (state == OES_INV && !ext->oe_urgent && !ext->oe_hp) {
938                 if (ext->oe_state == OES_ACTIVE) {
939                         ext->oe_urgent = 1;
940                 } else if (ext->oe_state == OES_CACHE) {
941                         ext->oe_urgent = 1;
942                         osc_extent_hold(ext);
943                         rc = 1;
944                 }
945         }
946         osc_object_unlock(obj);
947         if (rc == 1)
948                 osc_extent_release(env, ext);
949
950         /* wait for the extent until its state becomes @state */
951         rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state), &lwi);
952         if (rc == -ETIMEDOUT) {
953                 OSC_EXTENT_DUMP(D_ERROR, ext,
954                         "%s: wait ext to %u timedout, recovery in progress?\n",
955                         cli_name(osc_cli(obj)), state);
956
957                 lwi = LWI_INTR(NULL, NULL);
958                 rc = l_wait_event(ext->oe_waitq, extent_wait_cb(ext, state),
959                                   &lwi);
960         }
961         if (rc == 0 && ext->oe_rc < 0)
962                 rc = ext->oe_rc;
963         RETURN(rc);
964 }
965
966 /**
967  * Discard pages with index greater than @size. If @ext is overlapped with
968  * @size, then partial truncate happens.
969  */
970 static int osc_extent_truncate(struct osc_extent *ext, pgoff_t trunc_index,
971                                 bool partial)
972 {
973         struct lu_env         *env;
974         struct cl_io          *io;
975         struct osc_object     *obj = ext->oe_obj;
976         struct client_obd     *cli = osc_cli(obj);
977         struct osc_async_page *oap;
978         struct osc_async_page *tmp;
979         struct pagevec        *pvec;
980         int                    pages_in_chunk = 0;
981         int                    ppc_bits    = cli->cl_chunkbits -
982                                              PAGE_SHIFT;
983         __u64                  trunc_chunk = trunc_index >> ppc_bits;
984         int                    grants   = 0;
985         int                    nr_pages = 0;
986         int                    rc       = 0;
987         __u16                  refcheck;
988         ENTRY;
989
990         LASSERT(sanity_check(ext) == 0);
991         LASSERT(ext->oe_state == OES_TRUNC);
992         LASSERT(!ext->oe_urgent);
993
994         /* Request new lu_env.
995          * We can't use that env from osc_cache_truncate_start() because
996          * it's from lov_io_sub and not fully initialized. */
997         env = cl_env_get(&refcheck);
998         if (IS_ERR(env))
999                 RETURN(PTR_ERR(env));
1000
1001         io  = osc_env_thread_io(env);
1002         io->ci_obj = cl_object_top(osc2cl(obj));
1003         io->ci_ignore_layout = 1;
1004         pvec = &osc_env_info(env)->oti_pagevec;
1005         ll_pagevec_init(pvec, 0);
1006         rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
1007         if (rc < 0)
1008                 GOTO(out, rc);
1009
1010         /* discard all pages with index greater than trunc_index */
1011         list_for_each_entry_safe(oap, tmp, &ext->oe_pages,
1012                                      oap_pending_item) {
1013                 pgoff_t index = osc_index(oap2osc(oap));
1014                 struct cl_page  *page = oap2cl_page(oap);
1015
1016                 LASSERT(list_empty(&oap->oap_rpc_item));
1017
1018                 /* only discard the pages with their index greater than
1019                  * trunc_index, and ... */
1020                 if (index < trunc_index ||
1021                     (index == trunc_index && partial)) {
1022                         /* accounting how many pages remaining in the chunk
1023                          * so that we can calculate grants correctly. */
1024                         if (index >> ppc_bits == trunc_chunk)
1025                                 ++pages_in_chunk;
1026                         continue;
1027                 }
1028
1029                 list_del_init(&oap->oap_pending_item);
1030
1031                 cl_page_get(page);
1032                 lu_ref_add(&page->cp_reference, "truncate", current);
1033
1034                 if (cl_page_own(env, io, page) == 0) {
1035                         cl_page_discard(env, io, page);
1036                         cl_page_disown(env, io, page);
1037                 } else {
1038                         LASSERT(page->cp_state == CPS_FREEING);
1039                         LASSERT(0);
1040                 }
1041
1042                 lu_ref_del(&page->cp_reference, "truncate", current);
1043                 cl_pagevec_put(env, page, pvec);
1044
1045                 --ext->oe_nr_pages;
1046                 ++nr_pages;
1047         }
1048         pagevec_release(pvec);
1049
1050         EASSERTF(ergo(ext->oe_start >= trunc_index + !!partial,
1051                       ext->oe_nr_pages == 0),
1052                 ext, "trunc_index %lu, partial %d\n", trunc_index, partial);
1053
1054         osc_object_lock(obj);
1055         if (ext->oe_nr_pages == 0) {
1056                 LASSERT(pages_in_chunk == 0);
1057                 grants = ext->oe_grants;
1058                 ext->oe_grants = 0;
1059         } else { /* calculate how many grants we can free */
1060                 int     chunks = (ext->oe_end >> ppc_bits) - trunc_chunk;
1061                 pgoff_t last_index;
1062
1063
1064                 /* if there is no pages in this chunk, we can also free grants
1065                  * for the last chunk */
1066                 if (pages_in_chunk == 0) {
1067                         /* if this is the 1st chunk and no pages in this chunk,
1068                          * ext->oe_nr_pages must be zero, so we should be in
1069                          * the other if-clause. */
1070                         LASSERT(trunc_chunk > 0);
1071                         --trunc_chunk;
1072                         ++chunks;
1073                 }
1074
1075                 /* this is what we can free from this extent */
1076                 grants          = chunks << cli->cl_chunkbits;
1077                 ext->oe_grants -= grants;
1078                 last_index      = ((trunc_chunk + 1) << ppc_bits) - 1;
1079                 ext->oe_end     = min(last_index, ext->oe_max_end);
1080                 LASSERT(ext->oe_end >= ext->oe_start);
1081                 LASSERT(ext->oe_grants > 0);
1082         }
1083         osc_object_unlock(obj);
1084
1085         if (grants > 0 || nr_pages > 0)
1086                 osc_free_grant(cli, nr_pages, grants, grants);
1087
1088 out:
1089         cl_io_fini(env, io);
1090         cl_env_put(env, &refcheck);
1091         RETURN(rc);
1092 }
1093
1094 /**
1095  * This function is used to make the extent prepared for transfer.
1096  * A race with flusing page - ll_writepage() has to be handled cautiously.
1097  */
1098 static int osc_extent_make_ready(const struct lu_env *env,
1099                                  struct osc_extent *ext)
1100 {
1101         struct osc_async_page *oap;
1102         struct osc_async_page *last = NULL;
1103         struct osc_object *obj = ext->oe_obj;
1104         unsigned int page_count = 0;
1105         int rc;
1106         ENTRY;
1107
1108         /* we're going to grab page lock, so object lock must not be taken. */
1109         LASSERT(sanity_check(ext) == 0);
1110         /* in locking state, any process should not touch this extent. */
1111         EASSERT(ext->oe_state == OES_LOCKING, ext);
1112         EASSERT(ext->oe_owner != NULL, ext);
1113
1114         OSC_EXTENT_DUMP(D_CACHE, ext, "make ready\n");
1115
1116         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1117                 ++page_count;
1118                 if (last == NULL || last->oap_obj_off < oap->oap_obj_off)
1119                         last = oap;
1120
1121                 /* checking ASYNC_READY is race safe */
1122                 if ((oap->oap_async_flags & ASYNC_READY) != 0)
1123                         continue;
1124
1125                 rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
1126                 switch (rc) {
1127                 case 0:
1128                         spin_lock(&oap->oap_lock);
1129                         oap->oap_async_flags |= ASYNC_READY;
1130                         spin_unlock(&oap->oap_lock);
1131                         break;
1132                 case -EALREADY:
1133                         LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
1134                         break;
1135                 default:
1136                         LASSERTF(0, "unknown return code: %d\n", rc);
1137                 }
1138         }
1139
1140         LASSERT(page_count == ext->oe_nr_pages);
1141         LASSERT(last != NULL);
1142         /* the last page is the only one we need to refresh its count by
1143          * the size of file. */
1144         if (!(last->oap_async_flags & ASYNC_COUNT_STABLE)) {
1145                 int last_oap_count = osc_refresh_count(env, last, OBD_BRW_WRITE);
1146                 LASSERT(last_oap_count > 0);
1147                 LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
1148                 last->oap_count = last_oap_count;
1149                 spin_lock(&last->oap_lock);
1150                 last->oap_async_flags |= ASYNC_COUNT_STABLE;
1151                 spin_unlock(&last->oap_lock);
1152         }
1153
1154         /* for the rest of pages, we don't need to call osf_refresh_count()
1155          * because it's known they are not the last page */
1156         list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
1157                 if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
1158                         oap->oap_count = PAGE_SIZE - oap->oap_page_off;
1159                         spin_lock(&oap->oap_lock);
1160                         oap->oap_async_flags |= ASYNC_COUNT_STABLE;
1161                         spin_unlock(&oap->oap_lock);
1162                 }
1163         }
1164
1165         osc_object_lock(obj);
1166         osc_extent_state_set(ext, OES_RPC);
1167         osc_object_unlock(obj);
1168         /* get a refcount for RPC. */
1169         osc_extent_get(ext);
1170
1171         RETURN(0);
1172 }
1173
1174 /**
1175  * Quick and simple version of osc_extent_find(). This function is frequently
1176  * called to expand the extent for the same IO. To expand the extent, the
1177  * page index must be in the same or next chunk of ext->oe_end.
1178  */
1179 static int osc_extent_expand(struct osc_extent *ext, pgoff_t index,
1180                              unsigned int *grants)
1181 {
1182         struct osc_object *obj = ext->oe_obj;
1183         struct client_obd *cli = osc_cli(obj);
1184         struct osc_extent *next;
1185         int ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1186         pgoff_t chunk = index >> ppc_bits;
1187         pgoff_t end_chunk;
1188         pgoff_t end_index;
1189         unsigned int chunksize = 1 << cli->cl_chunkbits;
1190         int rc = 0;
1191         ENTRY;
1192
1193         LASSERT(ext->oe_max_end >= index && ext->oe_start <= index);
1194         osc_object_lock(obj);
1195         LASSERT(sanity_check_nolock(ext) == 0);
1196         end_chunk = ext->oe_end >> ppc_bits;
1197         if (chunk > end_chunk + 1)
1198                 GOTO(out, rc = -ERANGE);
1199
1200         if (end_chunk >= chunk)
1201                 GOTO(out, rc = 0);
1202
1203         LASSERT(end_chunk + 1 == chunk);
1204
1205         /* try to expand this extent to cover @index */
1206         end_index = min(ext->oe_max_end, ((chunk + 1) << ppc_bits) - 1);
1207
1208         /* don't go over the maximum extent size reported by server */
1209         if (end_index - ext->oe_start + 1 > cli->cl_max_extent_pages)
1210                 GOTO(out, rc = -ERANGE);
1211
1212         next = next_extent(ext);
1213         if (next != NULL && next->oe_start <= end_index)
1214                 /* complex mode - overlapped with the next extent,
1215                  * this case will be handled by osc_extent_find() */
1216                 GOTO(out, rc = -EAGAIN);
1217
1218         ext->oe_end = end_index;
1219         ext->oe_grants += chunksize;
1220         LASSERT(*grants >= chunksize);
1221         *grants -= chunksize;
1222         EASSERTF(osc_extent_is_overlapped(obj, ext) == 0, ext,
1223                  "overlapped after expanding for %lu.\n", index);
1224         EXIT;
1225
1226 out:
1227         osc_object_unlock(obj);
1228         RETURN(rc);
1229 }
1230
1231 static void osc_extent_tree_dump0(int level, struct osc_object *obj,
1232                                   const char *func, int line)
1233 {
1234         struct osc_extent *ext;
1235         int cnt;
1236
1237         if (!cfs_cdebug_show(level, DEBUG_SUBSYSTEM))
1238                 return;
1239
1240         CDEBUG(level, "Dump object %p extents at %s:%d, mppr: %u.\n",
1241                obj, func, line, osc_cli(obj)->cl_max_pages_per_rpc);
1242
1243         /* osc_object_lock(obj); */
1244         cnt = 1;
1245         for (ext = first_extent(obj); ext != NULL; ext = next_extent(ext))
1246                 OSC_EXTENT_DUMP(level, ext, "in tree %d.\n", cnt++);
1247
1248         cnt = 1;
1249         list_for_each_entry(ext, &obj->oo_hp_exts, oe_link)
1250                 OSC_EXTENT_DUMP(level, ext, "hp %d.\n", cnt++);
1251
1252         cnt = 1;
1253         list_for_each_entry(ext, &obj->oo_urgent_exts, oe_link)
1254                 OSC_EXTENT_DUMP(level, ext, "urgent %d.\n", cnt++);
1255
1256         cnt = 1;
1257         list_for_each_entry(ext, &obj->oo_reading_exts, oe_link)
1258                 OSC_EXTENT_DUMP(level, ext, "reading %d.\n", cnt++);
1259         /* osc_object_unlock(obj); */
1260 }
1261
1262 /* ------------------ osc extent end ------------------ */
1263
1264 static inline int osc_is_ready(struct osc_object *osc)
1265 {
1266         return !list_empty(&osc->oo_ready_item) ||
1267                !list_empty(&osc->oo_hp_ready_item);
1268 }
1269
1270 #define OSC_IO_DEBUG(OSC, STR, args...)                                        \
1271         CDEBUG(D_CACHE, "obj %p ready %d|%c|%c wr %d|%c|%c rd %d|%c " STR,     \
1272                (OSC), osc_is_ready(OSC),                                       \
1273                list_empty_marker(&(OSC)->oo_hp_ready_item),                    \
1274                list_empty_marker(&(OSC)->oo_ready_item),                       \
1275                atomic_read(&(OSC)->oo_nr_writes),                              \
1276                list_empty_marker(&(OSC)->oo_hp_exts),                          \
1277                list_empty_marker(&(OSC)->oo_urgent_exts),                      \
1278                atomic_read(&(OSC)->oo_nr_reads),                               \
1279                list_empty_marker(&(OSC)->oo_reading_exts),                     \
1280                ##args)
1281
1282 static int osc_make_ready(const struct lu_env *env, struct osc_async_page *oap,
1283                           int cmd)
1284 {
1285         struct osc_page *opg  = oap2osc_page(oap);
1286         struct cl_page  *page = oap2cl_page(oap);
1287         int result;
1288
1289         LASSERT(cmd == OBD_BRW_WRITE); /* no cached reads */
1290
1291         ENTRY;
1292         result = cl_page_make_ready(env, page, CRT_WRITE);
1293         if (result == 0)
1294                 opg->ops_submit_time = ktime_get();
1295         RETURN(result);
1296 }
1297
1298 static int osc_refresh_count(const struct lu_env *env,
1299                              struct osc_async_page *oap, int cmd)
1300 {
1301         struct osc_page  *opg = oap2osc_page(oap);
1302         pgoff_t index = osc_index(oap2osc(oap));
1303         struct cl_object *obj;
1304         struct cl_attr   *attr = &osc_env_info(env)->oti_attr;
1305         int result;
1306         loff_t kms;
1307
1308         /* readpage queues with _COUNT_STABLE, shouldn't get here. */
1309         LASSERT(!(cmd & OBD_BRW_READ));
1310         LASSERT(opg != NULL);
1311         obj = opg->ops_cl.cpl_obj;
1312
1313         cl_object_attr_lock(obj);
1314         result = cl_object_attr_get(env, obj, attr);
1315         cl_object_attr_unlock(obj);
1316         if (result < 0)
1317                 return result;
1318         kms = attr->cat_kms;
1319         if (cl_offset(obj, index) >= kms)
1320                 /* catch race with truncate */
1321                 return 0;
1322         else if (cl_offset(obj, index + 1) > kms)
1323                 /* catch sub-page write at end of file */
1324                 return kms % PAGE_SIZE;
1325         else
1326                 return PAGE_SIZE;
1327 }
1328
1329 static int osc_completion(const struct lu_env *env, struct osc_async_page *oap,
1330                           int cmd, int rc)
1331 {
1332         struct osc_page   *opg  = oap2osc_page(oap);
1333         struct cl_page    *page = oap2cl_page(oap);
1334         enum cl_req_type   crt;
1335         int srvlock;
1336
1337         ENTRY;
1338
1339         cmd &= ~OBD_BRW_NOQUOTA;
1340         LASSERTF(equi(page->cp_state == CPS_PAGEIN,  cmd == OBD_BRW_READ),
1341                  "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1342         LASSERTF(equi(page->cp_state == CPS_PAGEOUT, cmd == OBD_BRW_WRITE),
1343                 "cp_state:%u, cmd:%d\n", page->cp_state, cmd);
1344         LASSERT(opg->ops_transfer_pinned);
1345
1346         crt = cmd == OBD_BRW_READ ? CRT_READ : CRT_WRITE;
1347         /* Clear opg->ops_transfer_pinned before VM lock is released. */
1348         opg->ops_transfer_pinned = 0;
1349
1350         opg->ops_submit_time = ktime_set(0, 0);
1351         srvlock = oap->oap_brw_flags & OBD_BRW_SRVLOCK;
1352
1353         /* statistic */
1354         if (rc == 0 && srvlock) {
1355                 struct lu_device *ld    = opg->ops_cl.cpl_obj->co_lu.lo_dev;
1356                 struct osc_stats *stats = &lu2osc_dev(ld)->od_stats;
1357                 size_t bytes = oap->oap_count;
1358
1359                 if (crt == CRT_READ)
1360                         stats->os_lockless_reads += bytes;
1361                 else
1362                         stats->os_lockless_writes += bytes;
1363         }
1364
1365         /*
1366          * This has to be the last operation with the page, as locks are
1367          * released in cl_page_completion() and nothing except for the
1368          * reference counter protects page from concurrent reclaim.
1369          */
1370         lu_ref_del(&page->cp_reference, "transfer", page);
1371
1372         cl_page_completion(env, page, crt, rc);
1373         cl_page_put(env, page);
1374
1375         RETURN(0);
1376 }
1377
1378 #define OSC_DUMP_GRANT(lvl, cli, fmt, args...) do {                     \
1379         struct client_obd *__tmp = (cli);                               \
1380         CDEBUG(lvl, "%s: grant { dirty: %ld/%ld dirty_pages: %ld/%lu "  \
1381                "dropped: %ld avail: %ld, dirty_grant: %ld, "            \
1382                "reserved: %ld, flight: %d } lru {in list: %ld, "        \
1383                "left: %ld, waiters: %d }" fmt "\n",                     \
1384                cli_name(__tmp),                                         \
1385                __tmp->cl_dirty_pages, __tmp->cl_dirty_max_pages,        \
1386                atomic_long_read(&obd_dirty_pages), obd_max_dirty_pages, \
1387                __tmp->cl_lost_grant, __tmp->cl_avail_grant,             \
1388                __tmp->cl_dirty_grant,                                   \
1389                __tmp->cl_reserved_grant, __tmp->cl_w_in_flight,         \
1390                atomic_long_read(&__tmp->cl_lru_in_list),                \
1391                atomic_long_read(&__tmp->cl_lru_busy),                   \
1392                atomic_read(&__tmp->cl_lru_shrinkers), ##args);          \
1393 } while (0)
1394
1395 /* caller must hold loi_list_lock */
1396 static void osc_consume_write_grant(struct client_obd *cli,
1397                                     struct brw_page *pga)
1398 {
1399         assert_spin_locked(&cli->cl_loi_list_lock);
1400         LASSERT(!(pga->flag & OBD_BRW_FROM_GRANT));
1401         atomic_long_inc(&obd_dirty_pages);
1402         cli->cl_dirty_pages++;
1403         pga->flag |= OBD_BRW_FROM_GRANT;
1404         CDEBUG(D_CACHE, "using %lu grant credits for brw %p page %p\n",
1405                PAGE_SIZE, pga, pga->pg);
1406         osc_update_next_shrink(cli);
1407 }
1408
1409 /* the companion to osc_consume_write_grant, called when a brw has completed.
1410  * must be called with the loi lock held. */
1411 static void osc_release_write_grant(struct client_obd *cli,
1412                                     struct brw_page *pga)
1413 {
1414         ENTRY;
1415
1416         assert_spin_locked(&cli->cl_loi_list_lock);
1417         if (!(pga->flag & OBD_BRW_FROM_GRANT)) {
1418                 EXIT;
1419                 return;
1420         }
1421
1422         pga->flag &= ~OBD_BRW_FROM_GRANT;
1423         atomic_long_dec(&obd_dirty_pages);
1424         cli->cl_dirty_pages--;
1425         if (pga->flag & OBD_BRW_NOCACHE) {
1426                 pga->flag &= ~OBD_BRW_NOCACHE;
1427                 atomic_long_dec(&obd_dirty_transit_pages);
1428                 cli->cl_dirty_transit--;
1429         }
1430         EXIT;
1431 }
1432
1433 /**
1434  * To avoid sleeping with object lock held, it's good for us allocate enough
1435  * grants before entering into critical section.
1436  *
1437  * client_obd_list_lock held by caller
1438  */
1439 static int osc_reserve_grant(struct client_obd *cli, unsigned int bytes)
1440 {
1441         int rc = -EDQUOT;
1442
1443         if (cli->cl_avail_grant >= bytes) {
1444                 cli->cl_avail_grant    -= bytes;
1445                 cli->cl_reserved_grant += bytes;
1446                 rc = 0;
1447         }
1448         return rc;
1449 }
1450
1451 static void __osc_unreserve_grant(struct client_obd *cli,
1452                                   unsigned int reserved, unsigned int unused)
1453 {
1454         /* it's quite normal for us to get more grant than reserved.
1455          * Thinking about a case that two extents merged by adding a new
1456          * chunk, we can save one extent tax. If extent tax is greater than
1457          * one chunk, we can save more grant by adding a new chunk */
1458         cli->cl_reserved_grant -= reserved;
1459         if (unused > reserved) {
1460                 cli->cl_avail_grant += reserved;
1461                 cli->cl_lost_grant  += unused - reserved;
1462                 cli->cl_dirty_grant -= unused - reserved;
1463         } else {
1464                 cli->cl_avail_grant += unused;
1465                 cli->cl_dirty_grant += reserved - unused;
1466         }
1467 }
1468
1469 static void osc_unreserve_grant(struct client_obd *cli,
1470                                 unsigned int reserved, unsigned int unused)
1471 {
1472         spin_lock(&cli->cl_loi_list_lock);
1473         __osc_unreserve_grant(cli, reserved, unused);
1474         if (unused > 0)
1475                 osc_wake_cache_waiters(cli);
1476         spin_unlock(&cli->cl_loi_list_lock);
1477 }
1478
1479 /**
1480  * Free grant after IO is finished or canceled.
1481  *
1482  * @lost_grant is used to remember how many grants we have allocated but not
1483  * used, we should return these grants to OST. There're two cases where grants
1484  * can be lost:
1485  * 1. truncate;
1486  * 2. blocksize at OST is less than PAGE_SIZE and a partial page was
1487  *    written. In this case OST may use less chunks to serve this partial
1488  *    write. OSTs don't actually know the page size on the client side. so
1489  *    clients have to calculate lost grant by the blocksize on the OST.
1490  *    See filter_grant_check() for details.
1491  */
1492 static void osc_free_grant(struct client_obd *cli, unsigned int nr_pages,
1493                            unsigned int lost_grant, unsigned int dirty_grant)
1494 {
1495         unsigned long grant;
1496
1497         grant = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
1498
1499         spin_lock(&cli->cl_loi_list_lock);
1500         atomic_long_sub(nr_pages, &obd_dirty_pages);
1501         cli->cl_dirty_pages -= nr_pages;
1502         cli->cl_lost_grant += lost_grant;
1503         cli->cl_dirty_grant -= dirty_grant;
1504         if (cli->cl_avail_grant < grant && cli->cl_lost_grant >= grant) {
1505                 /* borrow some grant from truncate to avoid the case that
1506                  * truncate uses up all avail grant */
1507                 cli->cl_lost_grant -= grant;
1508                 cli->cl_avail_grant += grant;
1509         }
1510         osc_wake_cache_waiters(cli);
1511         spin_unlock(&cli->cl_loi_list_lock);
1512         CDEBUG(D_CACHE, "lost %u grant: %lu avail: %lu dirty: %lu/%lu\n",
1513                lost_grant, cli->cl_lost_grant,
1514                cli->cl_avail_grant, cli->cl_dirty_pages << PAGE_SHIFT,
1515                cli->cl_dirty_grant);
1516 }
1517
1518 /**
1519  * The companion to osc_enter_cache(), called when @oap is no longer part of
1520  * the dirty accounting due to error.
1521  */
1522 static void osc_exit_cache(struct client_obd *cli, struct osc_async_page *oap)
1523 {
1524         spin_lock(&cli->cl_loi_list_lock);
1525         osc_release_write_grant(cli, &oap->oap_brw_page);
1526         spin_unlock(&cli->cl_loi_list_lock);
1527 }
1528
1529 /**
1530  * Non-blocking version of osc_enter_cache() that consumes grant only when it
1531  * is available.
1532  */
1533 static int osc_enter_cache_try(struct client_obd *cli,
1534                                struct osc_async_page *oap,
1535                                int bytes, int transient)
1536 {
1537         int rc;
1538
1539         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1540
1541         rc = osc_reserve_grant(cli, bytes);
1542         if (rc < 0)
1543                 return 0;
1544
1545         if (cli->cl_dirty_pages < cli->cl_dirty_max_pages &&
1546             1 + atomic_long_read(&obd_dirty_pages) <= obd_max_dirty_pages) {
1547                 osc_consume_write_grant(cli, &oap->oap_brw_page);
1548                 if (transient) {
1549                         cli->cl_dirty_transit++;
1550                         atomic_long_inc(&obd_dirty_transit_pages);
1551                         oap->oap_brw_flags |= OBD_BRW_NOCACHE;
1552                 }
1553                 rc = 1;
1554         } else {
1555                 __osc_unreserve_grant(cli, bytes, bytes);
1556                 rc = 0;
1557         }
1558         return rc;
1559 }
1560
1561 static int ocw_granted(struct client_obd *cli, struct osc_cache_waiter *ocw)
1562 {
1563         int rc;
1564         spin_lock(&cli->cl_loi_list_lock);
1565         rc = list_empty(&ocw->ocw_entry);
1566         spin_unlock(&cli->cl_loi_list_lock);
1567         return rc;
1568 }
1569
1570 /**
1571  * The main entry to reserve dirty page accounting. Usually the grant reserved
1572  * in this function will be freed in bulk in osc_free_grant() unless it fails
1573  * to add osc cache, in that case, it will be freed in osc_exit_cache().
1574  *
1575  * The process will be put into sleep if it's already run out of grant.
1576  */
1577 static int osc_enter_cache(const struct lu_env *env, struct client_obd *cli,
1578                            struct osc_async_page *oap, int bytes)
1579 {
1580         struct osc_object       *osc = oap->oap_obj;
1581         struct lov_oinfo        *loi = osc->oo_oinfo;
1582         struct osc_cache_waiter  ocw;
1583         struct l_wait_info       lwi;
1584         int                      rc = -EDQUOT;
1585         ENTRY;
1586
1587         lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(AT_OFF ? obd_timeout : at_max),
1588                                NULL, LWI_ON_SIGNAL_NOOP, NULL);
1589
1590         OSC_DUMP_GRANT(D_CACHE, cli, "need:%d\n", bytes);
1591
1592         spin_lock(&cli->cl_loi_list_lock);
1593
1594         /* force the caller to try sync io.  this can jump the list
1595          * of queued writes and create a discontiguous rpc stream */
1596         if (OBD_FAIL_CHECK(OBD_FAIL_OSC_NO_GRANT) ||
1597             cli->cl_dirty_max_pages == 0 ||
1598             cli->cl_ar.ar_force_sync || loi->loi_ar.ar_force_sync) {
1599                 OSC_DUMP_GRANT(D_CACHE, cli, "forced sync i/o\n");
1600                 GOTO(out, rc = -EDQUOT);
1601         }
1602
1603         /* Hopefully normal case - cache space and write credits available */
1604         if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1605                 OSC_DUMP_GRANT(D_CACHE, cli, "granted from cache\n");
1606                 GOTO(out, rc = 0);
1607         }
1608
1609         /* We can get here for two reasons: too many dirty pages in cache, or
1610          * run out of grants. In both cases we should write dirty pages out.
1611          * Adding a cache waiter will trigger urgent write-out no matter what
1612          * RPC size will be.
1613          * The exiting condition is no avail grants and no dirty pages caching,
1614          * that really means there is no space on the OST. */
1615         init_waitqueue_head(&ocw.ocw_waitq);
1616         ocw.ocw_oap   = oap;
1617         ocw.ocw_grant = bytes;
1618         while (cli->cl_dirty_pages > 0 || cli->cl_w_in_flight > 0) {
1619                 list_add_tail(&ocw.ocw_entry, &cli->cl_cache_waiters);
1620                 ocw.ocw_rc = 0;
1621                 spin_unlock(&cli->cl_loi_list_lock);
1622
1623                 osc_io_unplug_async(env, cli, NULL);
1624
1625                 CDEBUG(D_CACHE, "%s: sleeping for cache space @ %p for %p\n",
1626                        cli_name(cli), &ocw, oap);
1627
1628                 rc = l_wait_event(ocw.ocw_waitq, ocw_granted(cli, &ocw), &lwi);
1629
1630                 spin_lock(&cli->cl_loi_list_lock);
1631
1632                 if (rc < 0) {
1633                         /* l_wait_event is interrupted by signal or timed out */
1634                         list_del_init(&ocw.ocw_entry);
1635                         break;
1636                 }
1637                 LASSERT(list_empty(&ocw.ocw_entry));
1638                 rc = ocw.ocw_rc;
1639
1640                 if (rc != -EDQUOT)
1641                         break;
1642                 if (osc_enter_cache_try(cli, oap, bytes, 0)) {
1643                         rc = 0;
1644                         break;
1645                 }
1646         }
1647
1648         switch (rc) {
1649         case 0:
1650                 OSC_DUMP_GRANT(D_CACHE, cli, "finally got grant space\n");
1651                 break;
1652         case -ETIMEDOUT:
1653                 OSC_DUMP_GRANT(D_CACHE, cli,
1654                                "timeout, fall back to sync i/o\n");
1655                 osc_extent_tree_dump(D_CACHE, osc);
1656                 /* fall back to synchronous I/O */
1657                 rc = -EDQUOT;
1658                 break;
1659         case -EINTR:
1660                 /* Ensures restartability - LU-3581 */
1661                 OSC_DUMP_GRANT(D_CACHE, cli, "interrupted\n");
1662                 rc = -ERESTARTSYS;
1663                 break;
1664         case -EDQUOT:
1665                 OSC_DUMP_GRANT(D_CACHE, cli,
1666                                "no grant space, fall back to sync i/o\n");
1667                 break;
1668         default:
1669                 CDEBUG(D_CACHE, "%s: event for cache space @ %p never arrived "
1670                        "due to %d, fall back to sync i/o\n",
1671                        cli_name(cli), &ocw, rc);
1672                 break;
1673         }
1674         EXIT;
1675 out:
1676         spin_unlock(&cli->cl_loi_list_lock);
1677         RETURN(rc);
1678 }
1679
1680 /* caller must hold loi_list_lock */
1681 void osc_wake_cache_waiters(struct client_obd *cli)
1682 {
1683         struct list_head *l, *tmp;
1684         struct osc_cache_waiter *ocw;
1685
1686         ENTRY;
1687         list_for_each_safe(l, tmp, &cli->cl_cache_waiters) {
1688                 ocw = list_entry(l, struct osc_cache_waiter, ocw_entry);
1689                 list_del_init(&ocw->ocw_entry);
1690
1691                 ocw->ocw_rc = -EDQUOT;
1692                 /* we can't dirty more */
1693                 if ((cli->cl_dirty_pages  >= cli->cl_dirty_max_pages) ||
1694                     (1 + atomic_long_read(&obd_dirty_pages) >
1695                      obd_max_dirty_pages)) {
1696                         CDEBUG(D_CACHE, "no dirty room: dirty: %ld "
1697                                "osc max %ld, sys max %ld\n",
1698                                cli->cl_dirty_pages, cli->cl_dirty_max_pages,
1699                                obd_max_dirty_pages);
1700                         goto wakeup;
1701                 }
1702
1703                 if (osc_enter_cache_try(cli, ocw->ocw_oap, ocw->ocw_grant, 0))
1704                         ocw->ocw_rc = 0;
1705 wakeup:
1706                 CDEBUG(D_CACHE, "wake up %p for oap %p, avail grant %ld, %d\n",
1707                        ocw, ocw->ocw_oap, cli->cl_avail_grant, ocw->ocw_rc);
1708
1709                 wake_up(&ocw->ocw_waitq);
1710         }
1711
1712         EXIT;
1713 }
1714 EXPORT_SYMBOL(osc_wake_cache_waiters);
1715
1716 static int osc_max_rpc_in_flight(struct client_obd *cli, struct osc_object *osc)
1717 {
1718         int hprpc = !!list_empty(&osc->oo_hp_exts);
1719         return rpcs_in_flight(cli) >= cli->cl_max_rpcs_in_flight + hprpc;
1720 }
1721
1722 /* This maintains the lists of pending pages to read/write for a given object
1723  * (lop).  This is used by osc_check_rpcs->osc_next_obj() and osc_list_maint()
1724  * to quickly find objects that are ready to send an RPC. */
1725 static int osc_makes_rpc(struct client_obd *cli, struct osc_object *osc,
1726                          int cmd)
1727 {
1728         int invalid_import = 0;
1729         ENTRY;
1730
1731         /* if we have an invalid import we want to drain the queued pages
1732          * by forcing them through rpcs that immediately fail and complete
1733          * the pages.  recovery relies on this to empty the queued pages
1734          * before canceling the locks and evicting down the llite pages */
1735         if ((cli->cl_import == NULL || cli->cl_import->imp_invalid))
1736                 invalid_import = 1;
1737
1738         if (cmd & OBD_BRW_WRITE) {
1739                 if (atomic_read(&osc->oo_nr_writes) == 0)
1740                         RETURN(0);
1741                 if (invalid_import) {
1742                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1743                         RETURN(1);
1744                 }
1745                 if (!list_empty(&osc->oo_hp_exts)) {
1746                         CDEBUG(D_CACHE, "high prio request forcing RPC\n");
1747                         RETURN(1);
1748                 }
1749                 if (!list_empty(&osc->oo_urgent_exts)) {
1750                         CDEBUG(D_CACHE, "urgent request forcing RPC\n");
1751                         RETURN(1);
1752                 }
1753                 /* trigger a write rpc stream as long as there are dirtiers
1754                  * waiting for space.  as they're waiting, they're not going to
1755                  * create more pages to coalesce with what's waiting.. */
1756                 if (!list_empty(&cli->cl_cache_waiters)) {
1757                         CDEBUG(D_CACHE, "cache waiters forcing RPC\n");
1758                         RETURN(1);
1759                 }
1760                 if (!list_empty(&osc->oo_full_exts)) {
1761                         CDEBUG(D_CACHE, "full extent ready, make an RPC\n");
1762                         RETURN(1);
1763                 }
1764         } else {
1765                 if (atomic_read(&osc->oo_nr_reads) == 0)
1766                         RETURN(0);
1767                 if (invalid_import) {
1768                         CDEBUG(D_CACHE, "invalid import forcing RPC\n");
1769                         RETURN(1);
1770                 }
1771                 /* all read are urgent. */
1772                 if (!list_empty(&osc->oo_reading_exts))
1773                         RETURN(1);
1774         }
1775
1776         RETURN(0);
1777 }
1778
1779 static void osc_update_pending(struct osc_object *obj, int cmd, int delta)
1780 {
1781         struct client_obd *cli = osc_cli(obj);
1782         if (cmd & OBD_BRW_WRITE) {
1783                 atomic_add(delta, &obj->oo_nr_writes);
1784                 atomic_add(delta, &cli->cl_pending_w_pages);
1785                 LASSERT(atomic_read(&obj->oo_nr_writes) >= 0);
1786         } else {
1787                 atomic_add(delta, &obj->oo_nr_reads);
1788                 atomic_add(delta, &cli->cl_pending_r_pages);
1789                 LASSERT(atomic_read(&obj->oo_nr_reads) >= 0);
1790         }
1791         OSC_IO_DEBUG(obj, "update pending cmd %d delta %d.\n", cmd, delta);
1792 }
1793
1794 static int osc_makes_hprpc(struct osc_object *obj)
1795 {
1796         return !list_empty(&obj->oo_hp_exts);
1797 }
1798
1799 static void on_list(struct list_head *item, struct list_head *list,
1800                     int should_be_on)
1801 {
1802         if (list_empty(item) && should_be_on)
1803                 list_add_tail(item, list);
1804         else if (!list_empty(item) && !should_be_on)
1805                 list_del_init(item);
1806 }
1807
1808 /* maintain the osc's cli list membership invariants so that osc_send_oap_rpc
1809  * can find pages to build into rpcs quickly */
1810 static int __osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1811 {
1812         if (osc_makes_hprpc(osc)) {
1813                 /* HP rpc */
1814                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list, 0);
1815                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 1);
1816         } else {
1817                 on_list(&osc->oo_hp_ready_item, &cli->cl_loi_hp_ready_list, 0);
1818                 on_list(&osc->oo_ready_item, &cli->cl_loi_ready_list,
1819                         osc_makes_rpc(cli, osc, OBD_BRW_WRITE) ||
1820                         osc_makes_rpc(cli, osc, OBD_BRW_READ));
1821         }
1822
1823         on_list(&osc->oo_write_item, &cli->cl_loi_write_list,
1824                 atomic_read(&osc->oo_nr_writes) > 0);
1825
1826         on_list(&osc->oo_read_item, &cli->cl_loi_read_list,
1827                 atomic_read(&osc->oo_nr_reads) > 0);
1828
1829         return osc_is_ready(osc);
1830 }
1831
1832 static int osc_list_maint(struct client_obd *cli, struct osc_object *osc)
1833 {
1834         int is_ready;
1835
1836         spin_lock(&cli->cl_loi_list_lock);
1837         is_ready = __osc_list_maint(cli, osc);
1838         spin_unlock(&cli->cl_loi_list_lock);
1839
1840         return is_ready;
1841 }
1842
1843 /* this is trying to propogate async writeback errors back up to the
1844  * application.  As an async write fails we record the error code for later if
1845  * the app does an fsync.  As long as errors persist we force future rpcs to be
1846  * sync so that the app can get a sync error and break the cycle of queueing
1847  * pages for which writeback will fail. */
1848 static void osc_process_ar(struct osc_async_rc *ar, __u64 xid,
1849                            int rc)
1850 {
1851         if (rc) {
1852                 if (!ar->ar_rc)
1853                         ar->ar_rc = rc;
1854
1855                 ar->ar_force_sync = 1;
1856                 ar->ar_min_xid = ptlrpc_sample_next_xid();
1857                 return;
1858
1859         }
1860
1861         if (ar->ar_force_sync && (xid >= ar->ar_min_xid))
1862                 ar->ar_force_sync = 0;
1863 }
1864
1865 /* this must be called holding the loi list lock to give coverage to exit_cache,
1866  * async_flag maintenance, and oap_request */
1867 static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
1868                               struct osc_async_page *oap, int sent, int rc)
1869 {
1870         struct osc_object *osc = oap->oap_obj;
1871         struct lov_oinfo  *loi = osc->oo_oinfo;
1872         __u64 xid = 0;
1873
1874         ENTRY;
1875         if (oap->oap_request != NULL) {
1876                 xid = ptlrpc_req_xid(oap->oap_request);
1877                 ptlrpc_req_finished(oap->oap_request);
1878                 oap->oap_request = NULL;
1879         }
1880
1881         /* As the transfer for this page is being done, clear the flags */
1882         spin_lock(&oap->oap_lock);
1883         oap->oap_async_flags = 0;
1884         spin_unlock(&oap->oap_lock);
1885         oap->oap_interrupted = 0;
1886
1887         if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
1888                 spin_lock(&cli->cl_loi_list_lock);
1889                 osc_process_ar(&cli->cl_ar, xid, rc);
1890                 osc_process_ar(&loi->loi_ar, xid, rc);
1891                 spin_unlock(&cli->cl_loi_list_lock);
1892         }
1893
1894         rc = osc_completion(env, oap, oap->oap_cmd, rc);
1895         if (rc)
1896                 CERROR("completion on oap %p obj %p returns %d.\n",
1897                        oap, osc, rc);
1898
1899         EXIT;
1900 }
1901
1902 struct extent_rpc_data {
1903         struct list_head        *erd_rpc_list;
1904         unsigned int            erd_page_count;
1905         unsigned int            erd_max_pages;
1906         unsigned int            erd_max_chunks;
1907         unsigned int            erd_max_extents;
1908 };
1909
1910 static inline unsigned osc_extent_chunks(const struct osc_extent *ext)
1911 {
1912         struct client_obd *cli = osc_cli(ext->oe_obj);
1913         unsigned ppc_bits = cli->cl_chunkbits - PAGE_SHIFT;
1914
1915         return (ext->oe_end >> ppc_bits) - (ext->oe_start >> ppc_bits) + 1;
1916 }
1917
1918 /**
1919  * Try to add extent to one RPC. We need to think about the following things:
1920  * - # of pages must not be over max_pages_per_rpc
1921  * - extent must be compatible with previous ones
1922  */
1923 static int try_to_add_extent_for_io(struct client_obd *cli,
1924                                     struct osc_extent *ext,
1925                                     struct extent_rpc_data *data)
1926 {
1927         struct osc_extent *tmp;
1928         unsigned int chunk_count;
1929         struct osc_async_page *oap = list_first_entry(&ext->oe_pages,
1930                                                       struct osc_async_page,
1931                                                       oap_pending_item);
1932         ENTRY;
1933
1934         EASSERT((ext->oe_state == OES_CACHE || ext->oe_state == OES_LOCK_DONE),
1935                 ext);
1936         OSC_EXTENT_DUMP(D_CACHE, ext, "trying to add this extent\n");
1937
1938         if (data->erd_max_extents == 0)
1939                 RETURN(0);
1940
1941         chunk_count = osc_extent_chunks(ext);
1942         EASSERTF(data->erd_page_count != 0 ||
1943                  chunk_count <= data->erd_max_chunks, ext,
1944                  "The first extent to be fit in a RPC contains %u chunks, "
1945                  "which is over the limit %u.\n", chunk_count,
1946                  data->erd_max_chunks);
1947         if (chunk_count > data->erd_max_chunks)
1948                 RETURN(0);
1949
1950         data->erd_max_pages = max(ext->oe_mppr, data->erd_max_pages);
1951         EASSERTF(data->erd_page_count != 0 ||
1952                 ext->oe_nr_pages <= data->erd_max_pages, ext,
1953                 "The first extent to be fit in a RPC contains %u pages, "
1954                 "which is over the limit %u.\n", ext->oe_nr_pages,
1955                 data->erd_max_pages);
1956         if (data->erd_page_count + ext->oe_nr_pages > data->erd_max_pages)
1957                 RETURN(0);
1958
1959         list_for_each_entry(tmp, data->erd_rpc_list, oe_link) {
1960                 struct osc_async_page *oap2;
1961                 oap2 = list_first_entry(&tmp->oe_pages, struct osc_async_page,
1962                                         oap_pending_item);
1963                 EASSERT(tmp->oe_owner == current, tmp);
1964 #if 0
1965                 if (overlapped(tmp, ext)) {
1966                         OSC_EXTENT_DUMP(D_ERROR, tmp, "overlapped %p.\n", ext);
1967                         EASSERT(0, ext);
1968                 }
1969 #endif
1970                 if (oap2cl_page(oap)->cp_type != oap2cl_page(oap2)->cp_type) {
1971                         CDEBUG(D_CACHE, "Do not permit different types of IO "
1972                                "in one RPC\n");
1973                         RETURN(0);
1974                 }
1975
1976                 if (tmp->oe_srvlock != ext->oe_srvlock ||
1977                     !tmp->oe_grants != !ext->oe_grants ||
1978                     tmp->oe_ndelay != ext->oe_ndelay ||
1979                     tmp->oe_no_merge || ext->oe_no_merge)
1980                         RETURN(0);
1981
1982                 /* remove break for strict check */
1983                 break;
1984         }
1985
1986         data->erd_max_extents--;
1987         data->erd_max_chunks -= chunk_count;
1988         data->erd_page_count += ext->oe_nr_pages;
1989         list_move_tail(&ext->oe_link, data->erd_rpc_list);
1990         ext->oe_owner = current;
1991         RETURN(1);
1992 }
1993
1994 /**
1995  * In order to prevent multiple ptlrpcd from breaking contiguous extents,
1996  * get_write_extent() takes all appropriate extents in atomic.
1997  *
1998  * The following policy is used to collect extents for IO:
1999  * 1. Add as many HP extents as possible;
2000  * 2. Add the first urgent extent in urgent extent list and take it out of
2001  *    urgent list;
2002  * 3. Add subsequent extents of this urgent extent;
2003  * 4. If urgent list is not empty, goto 2;
2004  * 5. Traverse the extent tree from the 1st extent;
2005  * 6. Above steps exit if there is no space in this RPC.
2006  */
2007 static unsigned int get_write_extents(struct osc_object *obj,
2008                                       struct list_head *rpclist)
2009 {
2010         struct client_obd *cli = osc_cli(obj);
2011         struct osc_extent *ext;
2012         struct extent_rpc_data data = {
2013                 .erd_rpc_list   = rpclist,
2014                 .erd_page_count = 0,
2015                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2016                 .erd_max_chunks = osc_max_write_chunks(cli),
2017                 .erd_max_extents = 256,
2018         };
2019
2020         LASSERT(osc_object_is_locked(obj));
2021         while (!list_empty(&obj->oo_hp_exts)) {
2022                 ext = list_entry(obj->oo_hp_exts.next, struct osc_extent,
2023                                  oe_link);
2024                 LASSERT(ext->oe_state == OES_CACHE);
2025                 if (!try_to_add_extent_for_io(cli, ext, &data))
2026                         return data.erd_page_count;
2027                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2028         }
2029         if (data.erd_page_count == data.erd_max_pages)
2030                 return data.erd_page_count;
2031
2032         while (!list_empty(&obj->oo_urgent_exts)) {
2033                 ext = list_entry(obj->oo_urgent_exts.next,
2034                                  struct osc_extent, oe_link);
2035                 if (!try_to_add_extent_for_io(cli, ext, &data))
2036                         return data.erd_page_count;
2037         }
2038         if (data.erd_page_count == data.erd_max_pages)
2039                 return data.erd_page_count;
2040
2041         /* One key difference between full extents and other extents: full
2042          * extents can usually only be added if the rpclist was empty, so if we
2043          * can't add one, we continue on to trying to add normal extents.  This
2044          * is so we don't miss adding extra extents to an RPC containing high
2045          * priority or urgent extents. */
2046         while (!list_empty(&obj->oo_full_exts)) {
2047                 ext = list_entry(obj->oo_full_exts.next,
2048                                  struct osc_extent, oe_link);
2049                 if (!try_to_add_extent_for_io(cli, ext, &data))
2050                         break;
2051         }
2052         if (data.erd_page_count == data.erd_max_pages)
2053                 return data.erd_page_count;
2054
2055         ext = first_extent(obj);
2056         while (ext != NULL) {
2057                 if ((ext->oe_state != OES_CACHE) ||
2058                     /* this extent may be already in current rpclist */
2059                     (!list_empty(&ext->oe_link) && ext->oe_owner != NULL)) {
2060                         ext = next_extent(ext);
2061                         continue;
2062                 }
2063
2064                 if (!try_to_add_extent_for_io(cli, ext, &data))
2065                         return data.erd_page_count;
2066
2067                 ext = next_extent(ext);
2068         }
2069         return data.erd_page_count;
2070 }
2071
2072 static int
2073 osc_send_write_rpc(const struct lu_env *env, struct client_obd *cli,
2074                    struct osc_object *osc)
2075 __must_hold(osc)
2076 {
2077         struct list_head   rpclist = LIST_HEAD_INIT(rpclist);
2078         struct osc_extent *ext;
2079         struct osc_extent *tmp;
2080         struct osc_extent *first = NULL;
2081         unsigned int page_count = 0;
2082         int srvlock = 0;
2083         int rc = 0;
2084         ENTRY;
2085
2086         LASSERT(osc_object_is_locked(osc));
2087
2088         page_count = get_write_extents(osc, &rpclist);
2089         LASSERT(equi(page_count == 0, list_empty(&rpclist)));
2090
2091         if (list_empty(&rpclist))
2092                 RETURN(0);
2093
2094         osc_update_pending(osc, OBD_BRW_WRITE, -page_count);
2095
2096         list_for_each_entry(ext, &rpclist, oe_link) {
2097                 LASSERT(ext->oe_state == OES_CACHE ||
2098                         ext->oe_state == OES_LOCK_DONE);
2099                 if (ext->oe_state == OES_CACHE)
2100                         osc_extent_state_set(ext, OES_LOCKING);
2101                 else
2102                         osc_extent_state_set(ext, OES_RPC);
2103         }
2104
2105         /* we're going to grab page lock, so release object lock because
2106          * lock order is page lock -> object lock. */
2107         osc_object_unlock(osc);
2108
2109         list_for_each_entry_safe(ext, tmp, &rpclist, oe_link) {
2110                 if (ext->oe_state == OES_LOCKING) {
2111                         rc = osc_extent_make_ready(env, ext);
2112                         if (unlikely(rc < 0)) {
2113                                 list_del_init(&ext->oe_link);
2114                                 osc_extent_finish(env, ext, 0, rc);
2115                                 continue;
2116                         }
2117                 }
2118                 if (first == NULL) {
2119                         first = ext;
2120                         srvlock = ext->oe_srvlock;
2121                 } else {
2122                         LASSERT(srvlock == ext->oe_srvlock);
2123                 }
2124         }
2125
2126         if (!list_empty(&rpclist)) {
2127                 LASSERT(page_count > 0);
2128                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_WRITE);
2129                 LASSERT(list_empty(&rpclist));
2130         }
2131
2132         osc_object_lock(osc);
2133         RETURN(rc);
2134 }
2135
2136 /**
2137  * prepare pages for ASYNC io and put pages in send queue.
2138  *
2139  * \param cmd OBD_BRW_* macroses
2140  * \param lop pending pages
2141  *
2142  * \return zero if no page added to send queue.
2143  * \return 1 if pages successfully added to send queue.
2144  * \return negative on errors.
2145  */
2146 static int
2147 osc_send_read_rpc(const struct lu_env *env, struct client_obd *cli,
2148                   struct osc_object *osc)
2149 __must_hold(osc)
2150 {
2151         struct osc_extent *ext;
2152         struct osc_extent *next;
2153         struct list_head rpclist = LIST_HEAD_INIT(rpclist);
2154         struct extent_rpc_data data = {
2155                 .erd_rpc_list   = &rpclist,
2156                 .erd_page_count = 0,
2157                 .erd_max_pages  = cli->cl_max_pages_per_rpc,
2158                 .erd_max_chunks = UINT_MAX,
2159                 .erd_max_extents = UINT_MAX,
2160         };
2161         int rc = 0;
2162         ENTRY;
2163
2164         LASSERT(osc_object_is_locked(osc));
2165         list_for_each_entry_safe(ext, next, &osc->oo_reading_exts, oe_link) {
2166                 EASSERT(ext->oe_state == OES_LOCK_DONE, ext);
2167                 if (!try_to_add_extent_for_io(cli, ext, &data))
2168                         break;
2169                 osc_extent_state_set(ext, OES_RPC);
2170                 EASSERT(ext->oe_nr_pages <= data.erd_max_pages, ext);
2171         }
2172         LASSERT(data.erd_page_count <= data.erd_max_pages);
2173
2174         osc_update_pending(osc, OBD_BRW_READ, -data.erd_page_count);
2175
2176         if (!list_empty(&rpclist)) {
2177                 osc_object_unlock(osc);
2178
2179                 rc = osc_build_rpc(env, cli, &rpclist, OBD_BRW_READ);
2180                 LASSERT(list_empty(&rpclist));
2181
2182                 osc_object_lock(osc);
2183         }
2184         RETURN(rc);
2185 }
2186
2187 #define list_to_obj(list, item) ({                                            \
2188         struct list_head *__tmp = (list)->next;                               \
2189         list_del_init(__tmp);                                         \
2190         list_entry(__tmp, struct osc_object, oo_##item);                      \
2191 })
2192
2193 /* This is called by osc_check_rpcs() to find which objects have pages that
2194  * we could be sending.  These lists are maintained by osc_makes_rpc(). */
2195 static struct osc_object *osc_next_obj(struct client_obd *cli)
2196 {
2197         ENTRY;
2198
2199         /* First return objects that have blocked locks so that they
2200          * will be flushed quickly and other clients can get the lock,
2201          * then objects which have pages ready to be stuffed into RPCs */
2202         if (!list_empty(&cli->cl_loi_hp_ready_list))
2203                 RETURN(list_to_obj(&cli->cl_loi_hp_ready_list, hp_ready_item));
2204         if (!list_empty(&cli->cl_loi_ready_list))
2205                 RETURN(list_to_obj(&cli->cl_loi_ready_list, ready_item));
2206
2207         /* then if we have cache waiters, return all objects with queued
2208          * writes.  This is especially important when many small files
2209          * have filled up the cache and not been fired into rpcs because
2210          * they don't pass the nr_pending/object threshhold */
2211         if (!list_empty(&cli->cl_cache_waiters) &&
2212             !list_empty(&cli->cl_loi_write_list))
2213                 RETURN(list_to_obj(&cli->cl_loi_write_list, write_item));
2214
2215         /* then return all queued objects when we have an invalid import
2216          * so that they get flushed */
2217         if (cli->cl_import == NULL || cli->cl_import->imp_invalid) {
2218                 if (!list_empty(&cli->cl_loi_write_list))
2219                         RETURN(list_to_obj(&cli->cl_loi_write_list,
2220                                            write_item));
2221                 if (!list_empty(&cli->cl_loi_read_list))
2222                         RETURN(list_to_obj(&cli->cl_loi_read_list,
2223                                            read_item));
2224         }
2225         RETURN(NULL);
2226 }
2227
2228 /* called with the loi list lock held */
2229 static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli)
2230 __must_hold(&cli->cl_loi_list_lock)
2231 {
2232         struct osc_object *osc;
2233         int rc = 0;
2234         ENTRY;
2235
2236         while ((osc = osc_next_obj(cli)) != NULL) {
2237                 struct cl_object *obj = osc2cl(osc);
2238                 struct lu_ref_link link;
2239
2240                 OSC_IO_DEBUG(osc, "%lu in flight\n", rpcs_in_flight(cli));
2241
2242                 if (osc_max_rpc_in_flight(cli, osc)) {
2243                         __osc_list_maint(cli, osc);
2244                         break;
2245                 }
2246
2247                 cl_object_get(obj);
2248                 spin_unlock(&cli->cl_loi_list_lock);
2249                 lu_object_ref_add_at(&obj->co_lu, &link, "check", current);
2250
2251                 /* attempt some read/write balancing by alternating between
2252                  * reads and writes in an object.  The makes_rpc checks here
2253                  * would be redundant if we were getting read/write work items
2254                  * instead of objects.  we don't want send_oap_rpc to drain a
2255                  * partial read pending queue when we're given this object to
2256                  * do io on writes while there are cache waiters */
2257                 osc_object_lock(osc);
2258                 if (osc_makes_rpc(cli, osc, OBD_BRW_WRITE)) {
2259                         rc = osc_send_write_rpc(env, cli, osc);
2260                         if (rc < 0) {
2261                                 CERROR("Write request failed with %d\n", rc);
2262
2263                                 /* osc_send_write_rpc failed, mostly because of
2264                                  * memory pressure.
2265                                  *
2266                                  * It can't break here, because if:
2267                                  *  - a page was submitted by osc_io_submit, so
2268                                  *    page locked;
2269                                  *  - no request in flight
2270                                  *  - no subsequent request
2271                                  * The system will be in live-lock state,
2272                                  * because there is no chance to call
2273                                  * osc_io_unplug() and osc_check_rpcs() any
2274                                  * more. pdflush can't help in this case,
2275                                  * because it might be blocked at grabbing
2276                                  * the page lock as we mentioned.
2277                                  *
2278                                  * Anyway, continue to drain pages. */
2279                                 /* break; */
2280                         }
2281                 }
2282                 if (osc_makes_rpc(cli, osc, OBD_BRW_READ)) {
2283                         rc = osc_send_read_rpc(env, cli, osc);
2284                         if (rc < 0)
2285                                 CERROR("Read request failed with %d\n", rc);
2286                 }
2287                 osc_object_unlock(osc);
2288
2289                 osc_list_maint(cli, osc);
2290                 lu_object_ref_del_at(&obj->co_lu, &link, "check", current);
2291                 cl_object_put(env, obj);
2292
2293                 spin_lock(&cli->cl_loi_list_lock);
2294         }
2295 }
2296
2297 int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
2298                    struct osc_object *osc, int async)
2299 {
2300         int rc = 0;
2301
2302         if (osc != NULL && osc_list_maint(cli, osc) == 0)
2303                 return 0;
2304
2305         if (!async) {
2306                 spin_lock(&cli->cl_loi_list_lock);
2307                 osc_check_rpcs(env, cli);
2308                 spin_unlock(&cli->cl_loi_list_lock);
2309         } else {
2310                 CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
2311                 LASSERT(cli->cl_writeback_work != NULL);
2312                 rc = ptlrpcd_queue_work(cli->cl_writeback_work);
2313         }
2314         return rc;
2315 }
2316 EXPORT_SYMBOL(osc_io_unplug0);
2317
2318 int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
2319                         struct page *page, loff_t offset)
2320 {
2321         struct obd_export     *exp = osc_export(osc);
2322         struct osc_async_page *oap = &ops->ops_oap;
2323         ENTRY;
2324
2325         if (!page)
2326                 return cfs_size_round(sizeof(*oap));
2327
2328         oap->oap_magic = OAP_MAGIC;
2329         oap->oap_cli = &exp->exp_obd->u.cli;
2330         oap->oap_obj = osc;
2331
2332         oap->oap_page = page;
2333         oap->oap_obj_off = offset;
2334         LASSERT(!(offset & ~PAGE_MASK));
2335
2336         if (cfs_capable(CFS_CAP_SYS_RESOURCE))
2337                 oap->oap_brw_flags = OBD_BRW_NOQUOTA;
2338
2339         INIT_LIST_HEAD(&oap->oap_pending_item);
2340         INIT_LIST_HEAD(&oap->oap_rpc_item);
2341
2342         spin_lock_init(&oap->oap_lock);
2343         CDEBUG(D_INFO, "oap %p page %p obj off %llu\n",
2344                oap, page, oap->oap_obj_off);
2345         RETURN(0);
2346 }
2347 EXPORT_SYMBOL(osc_prep_async_page);
2348
2349 int osc_queue_async_io(const struct lu_env *env, struct cl_io *io,
2350                        struct osc_page *ops)
2351 {
2352         struct osc_io *oio = osc_env_io(env);
2353         struct osc_extent     *ext = NULL;
2354         struct osc_async_page *oap = &ops->ops_oap;
2355         struct client_obd     *cli = oap->oap_cli;
2356         struct osc_object     *osc = oap->oap_obj;
2357         pgoff_t index;
2358         unsigned int tmp;
2359         unsigned int grants = 0;
2360         u32    brw_flags = OBD_BRW_ASYNC;
2361         int    cmd = OBD_BRW_WRITE;
2362         int    need_release = 0;
2363         int    rc = 0;
2364         ENTRY;
2365
2366         if (oap->oap_magic != OAP_MAGIC)
2367                 RETURN(-EINVAL);
2368
2369         if (cli->cl_import == NULL || cli->cl_import->imp_invalid)
2370                 RETURN(-EIO);
2371
2372         if (!list_empty(&oap->oap_pending_item) ||
2373             !list_empty(&oap->oap_rpc_item))
2374                 RETURN(-EBUSY);
2375
2376         /* Set the OBD_BRW_SRVLOCK before the page is queued. */
2377         brw_flags |= ops->ops_srvlock ? OBD_BRW_SRVLOCK : 0;
2378         if (cfs_capable(CFS_CAP_SYS_RESOURCE)) {
2379                 brw_flags |= OBD_BRW_NOQUOTA;
2380                 cmd |= OBD_BRW_NOQUOTA;
2381         }
2382
2383         /* check if the file's owner/group is over quota */
2384         if (!(cmd & OBD_BRW_NOQUOTA)) {
2385                 struct cl_object *obj;
2386                 struct cl_attr   *attr;
2387                 unsigned int qid[LL_MAXQUOTAS];
2388
2389                 obj = cl_object_top(&osc->oo_cl);
2390                 attr = &osc_env_info(env)->oti_attr;
2391
2392                 cl_object_attr_lock(obj);
2393                 rc = cl_object_attr_get(env, obj, attr);
2394                 cl_object_attr_unlock(obj);
2395
2396                 qid[USRQUOTA] = attr->cat_uid;
2397                 qid[GRPQUOTA] = attr->cat_gid;
2398                 qid[PRJQUOTA] = attr->cat_projid;
2399                 if (rc == 0 && osc_quota_chkdq(cli, qid) == NO_QUOTA)
2400                         rc = -EDQUOT;
2401                 if (rc)
2402                         RETURN(rc);
2403         }
2404
2405         oap->oap_cmd = cmd;
2406         oap->oap_page_off = ops->ops_from;
2407         oap->oap_count = ops->ops_to - ops->ops_from;
2408         /* No need to hold a lock here,
2409          * since this page is not in any list yet. */
2410         oap->oap_async_flags = 0;
2411         oap->oap_brw_flags = brw_flags;
2412
2413         OSC_IO_DEBUG(osc, "oap %p page %p added for cmd %d\n",
2414                      oap, oap->oap_page, oap->oap_cmd & OBD_BRW_RWMASK);
2415
2416         index = osc_index(oap2osc(oap));
2417
2418         /* Add this page into extent by the following steps:
2419          * 1. if there exists an active extent for this IO, mostly this page
2420          *    can be added to the active extent and sometimes we need to
2421          *    expand extent to accomodate this page;
2422          * 2. otherwise, a new extent will be allocated. */
2423
2424         ext = oio->oi_active;
2425         if (ext != NULL && ext->oe_start <= index && ext->oe_max_end >= index) {
2426                 /* one chunk plus extent overhead must be enough to write this
2427                  * page */
2428                 grants = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2429                 if (ext->oe_end >= index)
2430                         grants = 0;
2431
2432                 /* it doesn't need any grant to dirty this page */
2433                 spin_lock(&cli->cl_loi_list_lock);
2434                 rc = osc_enter_cache_try(cli, oap, grants, 0);
2435                 spin_unlock(&cli->cl_loi_list_lock);
2436                 if (rc == 0) { /* try failed */
2437                         grants = 0;
2438                         need_release = 1;
2439                 } else if (ext->oe_end < index) {
2440                         tmp = grants;
2441                         /* try to expand this extent */
2442                         rc = osc_extent_expand(ext, index, &tmp);
2443                         if (rc < 0) {
2444                                 need_release = 1;
2445                                 /* don't free reserved grant */
2446                         } else {
2447                                 OSC_EXTENT_DUMP(D_CACHE, ext,
2448                                                 "expanded for %lu.\n", index);
2449                                 osc_unreserve_grant(cli, grants, tmp);
2450                                 grants = 0;
2451                         }
2452                 }
2453                 rc = 0;
2454         } else if (ext != NULL) {
2455                 /* index is located outside of active extent */
2456                 need_release = 1;
2457         }
2458         if (need_release) {
2459                 osc_extent_release(env, ext);
2460                 oio->oi_active = NULL;
2461                 ext = NULL;
2462         }
2463
2464         if (ext == NULL) {
2465                 tmp = (1 << cli->cl_chunkbits) + cli->cl_grant_extent_tax;
2466
2467                 /* try to find new extent to cover this page */
2468                 LASSERT(oio->oi_active == NULL);
2469                 /* we may have allocated grant for this page if we failed
2470                  * to expand the previous active extent. */
2471                 LASSERT(ergo(grants > 0, grants >= tmp));
2472
2473                 rc = 0;
2474                 if (grants == 0) {
2475                         /* we haven't allocated grant for this page. */
2476                         rc = osc_enter_cache(env, cli, oap, tmp);
2477                         if (rc == 0)
2478                                 grants = tmp;
2479                 }
2480
2481                 tmp = grants;
2482                 if (rc == 0) {
2483                         ext = osc_extent_find(env, osc, index, &tmp);
2484                         if (IS_ERR(ext)) {
2485                                 LASSERT(tmp == grants);
2486                                 osc_exit_cache(cli, oap);
2487                                 rc = PTR_ERR(ext);
2488                                 ext = NULL;
2489                         } else {
2490                                 oio->oi_active = ext;
2491                         }
2492                 }
2493                 if (grants > 0)
2494                         osc_unreserve_grant(cli, grants, tmp);
2495         }
2496
2497         LASSERT(ergo(rc == 0, ext != NULL));
2498         if (ext != NULL) {
2499                 EASSERTF(ext->oe_end >= index && ext->oe_start <= index,
2500                          ext, "index = %lu.\n", index);
2501                 LASSERT((oap->oap_brw_flags & OBD_BRW_FROM_GRANT) != 0);
2502
2503                 osc_object_lock(osc);
2504                 if (ext->oe_nr_pages == 0)
2505                         ext->oe_srvlock = ops->ops_srvlock;
2506                 else
2507                         LASSERT(ext->oe_srvlock == ops->ops_srvlock);
2508                 ++ext->oe_nr_pages;
2509                 list_add_tail(&oap->oap_pending_item, &ext->oe_pages);
2510                 osc_object_unlock(osc);
2511
2512                 if (!ext->oe_layout_version)
2513                         ext->oe_layout_version = io->ci_layout_version;
2514         }
2515
2516         RETURN(rc);
2517 }
2518
2519 int osc_teardown_async_page(const struct lu_env *env,
2520                             struct osc_object *obj, struct osc_page *ops)
2521 {
2522         struct osc_async_page *oap = &ops->ops_oap;
2523         int rc = 0;
2524         ENTRY;
2525
2526         LASSERT(oap->oap_magic == OAP_MAGIC);
2527
2528         CDEBUG(D_INFO, "teardown oap %p page %p at index %lu.\n",
2529                oap, ops, osc_index(oap2osc(oap)));
2530
2531         if (!list_empty(&oap->oap_rpc_item)) {
2532                 CDEBUG(D_CACHE, "oap %p is not in cache.\n", oap);
2533                 rc = -EBUSY;
2534         } else if (!list_empty(&oap->oap_pending_item)) {
2535                 struct osc_extent *ext = NULL;
2536
2537                 osc_object_lock(obj);
2538                 ext = osc_extent_lookup(obj, osc_index(oap2osc(oap)));
2539                 osc_object_unlock(obj);
2540                 /* only truncated pages are allowed to be taken out.
2541                  * See osc_extent_truncate() and osc_cache_truncate_start()
2542                  * for details. */
2543                 if (ext != NULL && ext->oe_state != OES_TRUNC) {
2544                         OSC_EXTENT_DUMP(D_ERROR, ext, "trunc at %lu.\n",
2545                                         osc_index(oap2osc(oap)));
2546                         rc = -EBUSY;
2547                 }
2548                 if (ext != NULL)
2549                         osc_extent_put(env, ext);
2550         }
2551         RETURN(rc);
2552 }
2553
2554 /**
2555  * This is called when a page is picked up by kernel to write out.
2556  *
2557  * We should find out the corresponding extent and add the whole extent
2558  * into urgent list. The extent may be being truncated or used, handle it
2559  * carefully.
2560  */
2561 int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
2562                          struct osc_page *ops)
2563 {
2564         struct osc_extent *ext   = NULL;
2565         struct osc_object *obj   = cl2osc(ops->ops_cl.cpl_obj);
2566         struct cl_page    *cp    = ops->ops_cl.cpl_page;
2567         pgoff_t            index = osc_index(ops);
2568         struct osc_async_page *oap = &ops->ops_oap;
2569         bool unplug = false;
2570         int rc = 0;
2571         ENTRY;
2572
2573         osc_object_lock(obj);
2574         ext = osc_extent_lookup(obj, index);
2575         if (ext == NULL) {
2576                 osc_extent_tree_dump(D_ERROR, obj);
2577                 LASSERTF(0, "page index %lu is NOT covered.\n", index);
2578         }
2579
2580         switch (ext->oe_state) {
2581         case OES_RPC:
2582         case OES_LOCK_DONE:
2583                 CL_PAGE_DEBUG(D_ERROR, env, cp, "flush an in-rpc page?\n");
2584                 LASSERT(0);
2585                 break;
2586         case OES_LOCKING:
2587                 /* If we know this extent is being written out, we should abort
2588                  * so that the writer can make this page ready. Otherwise, there
2589                  * exists a deadlock problem because other process can wait for
2590                  * page writeback bit holding page lock; and meanwhile in
2591                  * vvp_page_make_ready(), we need to grab page lock before
2592                  * really sending the RPC. */
2593         case OES_TRUNC:
2594                 /* race with truncate, page will be redirtied */
2595         case OES_ACTIVE:
2596                 /* The extent is active so we need to abort and let the caller
2597                  * re-dirty the page. If we continued on here, and we were the
2598                  * one making the extent active, we could deadlock waiting for
2599                  * the page writeback to clear but it won't because the extent
2600                  * is active and won't be written out. */
2601                 GOTO(out, rc = -EAGAIN);
2602         default:
2603                 break;
2604         }
2605
2606         rc = cl_page_prep(env, io, cp, CRT_WRITE);
2607         if (rc)
2608                 GOTO(out, rc);
2609
2610         spin_lock(&oap->oap_lock);
2611         oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
2612         spin_unlock(&oap->oap_lock);
2613
2614         if (memory_pressure_get())
2615                 ext->oe_memalloc = 1;
2616
2617         ext->oe_urgent = 1;
2618         if (ext->oe_state == OES_CACHE) {
2619                 OSC_EXTENT_DUMP(D_CACHE, ext,
2620                                 "flush page %p make it urgent.\n", oap);
2621                 if (list_empty(&ext->oe_link))
2622                         list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2623                 unplug = true;
2624         }
2625         rc = 0;
2626         EXIT;
2627
2628 out:
2629         osc_object_unlock(obj);
2630         osc_extent_put(env, ext);
2631         if (unplug)
2632                 osc_io_unplug_async(env, osc_cli(obj), obj);
2633         return rc;
2634 }
2635
2636 /**
2637  * this is called when a sync waiter receives an interruption.  Its job is to
2638  * get the caller woken as soon as possible.  If its page hasn't been put in an
2639  * rpc yet it can dequeue immediately.  Otherwise it has to mark the rpc as
2640  * desiring interruption which will forcefully complete the rpc once the rpc
2641  * has timed out.
2642  */
2643 int osc_cancel_async_page(const struct lu_env *env, struct osc_page *ops)
2644 {
2645         struct osc_async_page *oap = &ops->ops_oap;
2646         struct osc_object     *obj = oap->oap_obj;
2647         struct client_obd     *cli = osc_cli(obj);
2648         struct osc_extent     *ext;
2649         struct osc_extent     *found = NULL;
2650         struct list_head            *plist;
2651         pgoff_t index = osc_index(ops);
2652         int     rc = -EBUSY;
2653         int     cmd;
2654         ENTRY;
2655
2656         LASSERT(!oap->oap_interrupted);
2657         oap->oap_interrupted = 1;
2658
2659         /* Find out the caching extent */
2660         osc_object_lock(obj);
2661         if (oap->oap_cmd & OBD_BRW_WRITE) {
2662                 plist = &obj->oo_urgent_exts;
2663                 cmd   = OBD_BRW_WRITE;
2664         } else {
2665                 plist = &obj->oo_reading_exts;
2666                 cmd   = OBD_BRW_READ;
2667         }
2668         list_for_each_entry(ext, plist, oe_link) {
2669                 if (ext->oe_start <= index && ext->oe_end >= index) {
2670                         LASSERT(ext->oe_state == OES_LOCK_DONE);
2671                         /* For OES_LOCK_DONE state extent, it has already held
2672                          * a refcount for RPC. */
2673                         found = osc_extent_get(ext);
2674                         break;
2675                 }
2676         }
2677         if (found != NULL) {
2678                 list_del_init(&found->oe_link);
2679                 osc_update_pending(obj, cmd, -found->oe_nr_pages);
2680                 osc_object_unlock(obj);
2681
2682                 osc_extent_finish(env, found, 0, -EINTR);
2683                 osc_extent_put(env, found);
2684                 rc = 0;
2685         } else {
2686                 osc_object_unlock(obj);
2687                 /* ok, it's been put in an rpc. only one oap gets a request
2688                  * reference */
2689                 if (oap->oap_request != NULL) {
2690                         ptlrpc_mark_interrupted(oap->oap_request);
2691                         ptlrpcd_wake(oap->oap_request);
2692                         ptlrpc_req_finished(oap->oap_request);
2693                         oap->oap_request = NULL;
2694                 }
2695         }
2696
2697         osc_list_maint(cli, obj);
2698         RETURN(rc);
2699 }
2700
2701 int osc_queue_sync_pages(const struct lu_env *env, const struct cl_io *io,
2702                          struct osc_object *obj, struct list_head *list,
2703                          int brw_flags)
2704 {
2705         struct client_obd     *cli = osc_cli(obj);
2706         struct osc_extent     *ext;
2707         struct osc_async_page *oap;
2708         int     page_count = 0;
2709         int     mppr       = cli->cl_max_pages_per_rpc;
2710         bool    can_merge   = true;
2711         pgoff_t start      = CL_PAGE_EOF;
2712         pgoff_t end        = 0;
2713         ENTRY;
2714
2715         list_for_each_entry(oap, list, oap_pending_item) {
2716                 struct osc_page *opg = oap2osc_page(oap);
2717                 pgoff_t index = osc_index(opg);
2718
2719                 if (index > end)
2720                         end = index;
2721                 if (index < start)
2722                         start = index;
2723                 ++page_count;
2724                 mppr <<= (page_count > mppr);
2725
2726                 if (unlikely(opg->ops_from > 0 || opg->ops_to < PAGE_SIZE))
2727                         can_merge = false;
2728         }
2729
2730         ext = osc_extent_alloc(obj);
2731         if (ext == NULL) {
2732                 struct osc_async_page *tmp;
2733
2734                 list_for_each_entry_safe(oap, tmp, list, oap_pending_item) {
2735                         list_del_init(&oap->oap_pending_item);
2736                         osc_ap_completion(env, cli, oap, 0, -ENOMEM);
2737                 }
2738                 RETURN(-ENOMEM);
2739         }
2740
2741         ext->oe_rw = !!(brw_flags & OBD_BRW_READ);
2742         ext->oe_sync = 1;
2743         ext->oe_no_merge = !can_merge;
2744         ext->oe_urgent = 1;
2745         ext->oe_start = start;
2746         ext->oe_end = ext->oe_max_end = end;
2747         ext->oe_obj = obj;
2748         ext->oe_srvlock = !!(brw_flags & OBD_BRW_SRVLOCK);
2749         ext->oe_ndelay = !!(brw_flags & OBD_BRW_NDELAY);
2750         ext->oe_nr_pages = page_count;
2751         ext->oe_mppr = mppr;
2752         list_splice_init(list, &ext->oe_pages);
2753         ext->oe_layout_version = io->ci_layout_version;
2754
2755         osc_object_lock(obj);
2756         /* Reuse the initial refcount for RPC, don't drop it */
2757         osc_extent_state_set(ext, OES_LOCK_DONE);
2758         if (!ext->oe_rw) { /* write */
2759                 list_add_tail(&ext->oe_link, &obj->oo_urgent_exts);
2760                 osc_update_pending(obj, OBD_BRW_WRITE, page_count);
2761         } else {
2762                 list_add_tail(&ext->oe_link, &obj->oo_reading_exts);
2763                 osc_update_pending(obj, OBD_BRW_READ, page_count);
2764         }
2765         osc_object_unlock(obj);
2766
2767         osc_io_unplug_async(env, cli, obj);
2768         RETURN(0);
2769 }
2770
2771 /**
2772  * Called by osc_io_setattr_start() to freeze and destroy covering extents.
2773  */
2774 int osc_cache_truncate_start(const struct lu_env *env, struct osc_object *obj,
2775                              __u64 size, struct osc_extent **extp)
2776 {
2777         struct client_obd *cli = osc_cli(obj);
2778         struct osc_extent *ext;
2779         struct osc_extent *waiting = NULL;
2780         pgoff_t index;
2781         struct list_head list = LIST_HEAD_INIT(list);
2782         int result = 0;
2783         bool partial;
2784         ENTRY;
2785
2786         /* pages with index greater or equal to index will be truncated. */
2787         index = cl_index(osc2cl(obj), size);
2788         partial = size > cl_offset(osc2cl(obj), index);
2789
2790 again:
2791         osc_object_lock(obj);
2792         ext = osc_extent_search(obj, index);
2793         if (ext == NULL)
2794                 ext = first_extent(obj);
2795         else if (ext->oe_end < index)
2796                 ext = next_extent(ext);
2797         while (ext != NULL) {
2798                 EASSERT(ext->oe_state != OES_TRUNC, ext);
2799
2800                 if (ext->oe_state > OES_CACHE || ext->oe_urgent) {
2801                         /* if ext is in urgent state, it means there must exist
2802                          * a page already having been flushed by write_page().
2803                          * We have to wait for this extent because we can't
2804                          * truncate that page. */
2805                         OSC_EXTENT_DUMP(D_CACHE, ext,
2806                                         "waiting for busy extent\n");
2807                         waiting = osc_extent_get(ext);
2808                         break;
2809                 }
2810
2811                 OSC_EXTENT_DUMP(D_CACHE, ext, "try to trunc:%llu.\n", size);
2812
2813                 osc_extent_get(ext);
2814                 if (ext->oe_state == OES_ACTIVE) {
2815                         /* though we grab inode mutex for write path, but we
2816                          * release it before releasing extent(in osc_io_end()),
2817                          * so there is a race window that an extent is still
2818                          * in OES_ACTIVE when truncate starts. */
2819                         LASSERT(!ext->oe_trunc_pending);
2820                         ext->oe_trunc_pending = 1;
2821                 } else {
2822                         EASSERT(ext->oe_state == OES_CACHE, ext);
2823                         osc_extent_state_set(ext, OES_TRUNC);
2824                         osc_update_pending(obj, OBD_BRW_WRITE,
2825                                            -ext->oe_nr_pages);
2826                 }
2827                 /* This extent could be on the full extents list, that's OK */
2828                 EASSERT(!ext->oe_hp && !ext->oe_urgent, ext);
2829                 if (!list_empty(&ext->oe_link))
2830                         list_move_tail(&ext->oe_link, &list);
2831                 else
2832                         list_add_tail(&ext->oe_link, &list);
2833
2834                 ext = next_extent(ext);
2835         }
2836         osc_object_unlock(obj);
2837
2838         osc_list_maint(cli, obj);
2839
2840         while (!list_empty(&list)) {
2841                 int rc;
2842
2843                 ext = list_entry(list.next, struct osc_extent, oe_link);
2844                 list_del_init(&ext->oe_link);
2845
2846                 /* extent may be in OES_ACTIVE state because inode mutex
2847                  * is released before osc_io_end() in file write case */
2848                 if (ext->oe_state != OES_TRUNC)
2849                         osc_extent_wait(env, ext, OES_TRUNC);
2850
2851                 rc = osc_extent_truncate(ext, index, partial);
2852                 if (rc < 0) {
2853                         if (result == 0)
2854                                 result = rc;
2855
2856                         OSC_EXTENT_DUMP(D_ERROR, ext,
2857                                         "truncate error %d\n", rc);
2858                 } else if (ext->oe_nr_pages == 0) {
2859                         osc_extent_remove(ext);
2860                 } else {
2861                         /* this must be an overlapped extent which means only
2862                          * part of pages in this extent have been truncated.
2863                          */
2864                         EASSERTF(ext->oe_start <= index, ext,
2865                                  "trunc index = %lu/%d.\n", index, partial);
2866                         /* fix index to skip this partially truncated extent */
2867                         index = ext->oe_end + 1;
2868                         partial = false;
2869
2870                         /* we need to hold this extent in OES_TRUNC state so
2871                          * that no writeback will happen. This is to avoid
2872                          * BUG 17397.
2873                          * Only partial truncate can reach here, if @size is
2874                          * not zero, the caller should provide a valid @extp. */
2875                         LASSERT(*extp == NULL);
2876                         *extp = osc_extent_get(ext);
2877                         OSC_EXTENT_DUMP(D_CACHE, ext,
2878                                         "trunc at %llu\n", size);
2879                 }
2880                 osc_extent_put(env, ext);
2881         }
2882         if (waiting != NULL) {
2883                 int rc;
2884
2885                 /* ignore the result of osc_extent_wait the write initiator
2886                  * should take care of it. */
2887                 rc = osc_extent_wait(env, waiting, OES_INV);
2888                 if (rc < 0)
2889                         OSC_EXTENT_DUMP(D_CACHE, waiting, "error: %d.\n", rc);
2890
2891                 osc_extent_put(env, waiting);
2892                 waiting = NULL;
2893                 goto again;
2894         }
2895         RETURN(result);
2896 }
2897 EXPORT_SYMBOL(osc_cache_truncate_start);
2898
2899 /**
2900  * Called after osc_io_setattr_end to add oio->oi_trunc back to cache.
2901  */
2902 void osc_cache_truncate_end(const struct lu_env *env, struct osc_extent *ext)
2903 {
2904         if (ext != NULL) {
2905                 struct osc_object *obj = ext->oe_obj;
2906                 bool unplug = false;
2907
2908                 EASSERT(ext->oe_nr_pages > 0, ext);
2909                 EASSERT(ext->oe_state == OES_TRUNC, ext);
2910                 EASSERT(!ext->oe_urgent, ext);
2911
2912                 OSC_EXTENT_DUMP(D_CACHE, ext, "trunc -> cache.\n");
2913                 osc_object_lock(obj);
2914                 osc_extent_state_set(ext, OES_CACHE);
2915                 if (ext->oe_fsync_wait && !ext->oe_urgent) {
2916                         ext->oe_urgent = 1;
2917                         list_move_tail(&ext->oe_link, &obj->oo_urgent_exts);
2918                         unplug = true;
2919                 }
2920                 osc_update_pending(obj, OBD_BRW_WRITE, ext->oe_nr_pages);
2921                 osc_object_unlock(obj);
2922                 osc_extent_put(env, ext);
2923
2924                 if (unplug)
2925                         osc_io_unplug_async(env, osc_cli(obj), obj);
2926         }
2927 }
2928
2929 /**
2930  * Wait for extents in a specific range to be written out.
2931  * The caller must have called osc_cache_writeback_range() to issue IO
2932  * otherwise it will take a long time for this function to finish.
2933  *
2934  * Caller must hold inode_mutex , or cancel exclusive dlm lock so that
2935  * nobody else can dirty this range of file while we're waiting for
2936  * extents to be written.
2937  */
2938 int osc_cache_wait_range(const struct lu_env *env, struct osc_object *obj,
2939                          pgoff_t start, pgoff_t end)
2940 {
2941         struct osc_extent *ext;
2942         pgoff_t index = start;
2943         int     result = 0;
2944         ENTRY;
2945
2946 again:
2947         osc_object_lock(obj);
2948         ext = osc_extent_search(obj, index);
2949         if (ext == NULL)
2950                 ext = first_extent(obj);
2951         else if (ext->oe_end < index)
2952                 ext = next_extent(ext);
2953         while (ext != NULL) {
2954                 int rc;
2955
2956                 if (ext->oe_start > end)
2957                         break;
2958
2959                 if (!ext->oe_fsync_wait) {
2960                         ext = next_extent(ext);
2961                         continue;
2962                 }
2963
2964                 EASSERT(ergo(ext->oe_state == OES_CACHE,
2965                              ext->oe_hp || ext->oe_urgent), ext);
2966                 EASSERT(ergo(ext->oe_state == OES_ACTIVE,
2967                              !ext->oe_hp && ext->oe_urgent), ext);
2968
2969                 index = ext->oe_end + 1;
2970                 osc_extent_get(ext);
2971                 osc_object_unlock(obj);
2972
2973                 rc = osc_extent_wait(env, ext, OES_INV);
2974                 if (result == 0)
2975                         result = rc;
2976                 osc_extent_put(env, ext);
2977                 goto again;
2978         }
2979         osc_object_unlock(obj);
2980
2981         OSC_IO_DEBUG(obj, "sync file range.\n");
2982         RETURN(result);
2983 }
2984 EXPORT_SYMBOL(osc_cache_wait_range);
2985
2986 /**
2987  * Called to write out a range of osc object.
2988  *
2989  * @hp     : should be set this is caused by lock cancel;
2990  * @discard: is set if dirty pages should be dropped - file will be deleted or
2991  *         truncated, this implies there is no partially discarding extents.
2992  *
2993  * Return how many pages will be issued, or error code if error occurred.
2994  */
2995 int osc_cache_writeback_range(const struct lu_env *env, struct osc_object *obj,
2996                               pgoff_t start, pgoff_t end, int hp, int discard)
2997 {
2998         struct osc_extent *ext;
2999         struct list_head discard_list = LIST_HEAD_INIT(discard_list);
3000         bool unplug = false;
3001         int result = 0;
3002         ENTRY;
3003
3004         osc_object_lock(obj);
3005         ext = osc_extent_search(obj, start);
3006         if (ext == NULL)
3007                 ext = first_extent(obj);
3008         else if (ext->oe_end < start)
3009                 ext = next_extent(ext);
3010         while (ext != NULL) {
3011                 if (ext->oe_start > end)
3012                         break;
3013
3014                 ext->oe_fsync_wait = 1;
3015                 switch (ext->oe_state) {
3016                 case OES_CACHE:
3017                         result += ext->oe_nr_pages;
3018                         if (!discard) {
3019                                 struct list_head *list = NULL;
3020                                 if (hp) {
3021                                         EASSERT(!ext->oe_hp, ext);
3022                                         ext->oe_hp = 1;
3023                                         list = &obj->oo_hp_exts;
3024                                 } else if (!ext->oe_urgent) {
3025                                         ext->oe_urgent = 1;
3026                                         list = &obj->oo_urgent_exts;
3027                                 }
3028                                 if (list != NULL)
3029                                         list_move_tail(&ext->oe_link, list);
3030                                 unplug = true;
3031                         } else {
3032                                 /* the only discarder is lock cancelling, so
3033                                  * [start, end] must contain this extent */
3034                                 EASSERT(ext->oe_start >= start &&
3035                                         ext->oe_max_end <= end, ext);
3036                                 osc_extent_state_set(ext, OES_LOCKING);
3037                                 ext->oe_owner = current;
3038                                 list_move_tail(&ext->oe_link,
3039                                                    &discard_list);
3040                                 osc_update_pending(obj, OBD_BRW_WRITE,
3041                                                    -ext->oe_nr_pages);
3042                         }
3043                         break;
3044                 case OES_ACTIVE:
3045                         /* It's pretty bad to wait for ACTIVE extents, because
3046                          * we don't know how long we will wait for it to be
3047                          * flushed since it may be blocked at awaiting more
3048                          * grants. We do this for the correctness of fsync. */
3049                         LASSERT(hp == 0 && discard == 0);
3050                         ext->oe_urgent = 1;
3051                         break;
3052                 case OES_TRUNC:
3053                         /* this extent is being truncated, can't do anything
3054                          * for it now. it will be set to urgent after truncate
3055                          * is finished in osc_cache_truncate_end(). */
3056                 default:
3057                         break;
3058                 }
3059                 ext = next_extent(ext);
3060         }
3061         osc_object_unlock(obj);
3062
3063         LASSERT(ergo(!discard, list_empty(&discard_list)));
3064         if (!list_empty(&discard_list)) {
3065                 struct osc_extent *tmp;
3066                 int rc;
3067
3068                 osc_list_maint(osc_cli(obj), obj);
3069                 list_for_each_entry_safe(ext, tmp, &discard_list, oe_link) {
3070                         list_del_init(&ext->oe_link);
3071                         EASSERT(ext->oe_state == OES_LOCKING, ext);
3072
3073                         /* Discard caching pages. We don't actually write this
3074                          * extent out but we complete it as if we did. */
3075                         rc = osc_extent_make_ready(env, ext);
3076                         if (unlikely(rc < 0)) {
3077                                 OSC_EXTENT_DUMP(D_ERROR, ext,
3078                                                 "make_ready returned %d\n", rc);
3079                                 if (result >= 0)
3080                                         result = rc;
3081                         }
3082
3083                         /* finish the extent as if the pages were sent */
3084                         osc_extent_finish(env, ext, 0, 0);
3085                 }
3086         }
3087
3088         if (unplug)
3089                 osc_io_unplug(env, osc_cli(obj), obj);
3090
3091         if (hp || discard) {
3092                 int rc;
3093                 rc = osc_cache_wait_range(env, obj, start, end);
3094                 if (result >= 0 && rc < 0)
3095                         result = rc;
3096         }
3097
3098         OSC_IO_DEBUG(obj, "pageout [%lu, %lu], %d.\n", start, end, result);
3099         RETURN(result);
3100 }
3101 EXPORT_SYMBOL(osc_cache_writeback_range);
3102
3103 /**
3104  * Returns a list of pages by a given [start, end] of \a obj.
3105  *
3106  * \param resched If not NULL, then we give up before hogging CPU for too
3107  * long and set *resched = 1, in that case caller should implement a retry
3108  * logic.
3109  *
3110  * Gang tree lookup (radix_tree_gang_lookup()) optimization is absolutely
3111  * crucial in the face of [offset, EOF] locks.
3112  *
3113  * Return at least one page in @queue unless there is no covered page.
3114  */
3115 int osc_page_gang_lookup(const struct lu_env *env, struct cl_io *io,
3116                         struct osc_object *osc, pgoff_t start, pgoff_t end,
3117                         osc_page_gang_cbt cb, void *cbdata)
3118 {
3119         struct osc_page *ops;
3120         struct pagevec  *pagevec;
3121         void            **pvec;
3122         pgoff_t         idx;
3123         unsigned int    nr;
3124         unsigned int    i;
3125         unsigned int    j;
3126         int             res = CLP_GANG_OKAY;
3127         bool            tree_lock = true;
3128         ENTRY;
3129
3130         idx = start;
3131         pvec = osc_env_info(env)->oti_pvec;
3132         pagevec = &osc_env_info(env)->oti_pagevec;
3133         ll_pagevec_init(pagevec, 0);
3134         spin_lock(&osc->oo_tree_lock);
3135         while ((nr = radix_tree_gang_lookup(&osc->oo_tree, pvec,
3136                                             idx, OTI_PVEC_SIZE)) > 0) {
3137                 struct cl_page *page;
3138                 bool end_of_region = false;
3139
3140                 for (i = 0, j = 0; i < nr; ++i) {
3141                         ops = pvec[i];
3142                         pvec[i] = NULL;
3143
3144                         idx = osc_index(ops);
3145                         if (idx > end) {
3146                                 end_of_region = true;
3147                                 break;
3148                         }
3149
3150                         page = ops->ops_cl.cpl_page;
3151                         LASSERT(page->cp_type == CPT_CACHEABLE);
3152                         if (page->cp_state == CPS_FREEING)
3153                                 continue;
3154
3155                         cl_page_get(page);
3156                         lu_ref_add_atomic(&page->cp_reference,
3157                                           "gang_lookup", current);
3158                         pvec[j++] = ops;
3159                 }
3160                 ++idx;
3161
3162                 /*
3163                  * Here a delicate locking dance is performed. Current thread
3164                  * holds a reference to a page, but has to own it before it
3165                  * can be placed into queue. Owning implies waiting, so
3166                  * radix-tree lock is to be released. After a wait one has to
3167                  * check that pages weren't truncated (cl_page_own() returns
3168                  * error in the latter case).
3169                  */
3170                 spin_unlock(&osc->oo_tree_lock);
3171                 tree_lock = false;
3172
3173                 for (i = 0; i < j; ++i) {